Final Report Summary - ELYGRID (Improvements to Integrate High Pressure Alkaline Electrolysers for Electricity/H2 production from Renewable Energies to Balance the Grid.)
Executive Summary:
The project has achieved significant results in all the fields. A new cell topology has been developed with better efficiency and working at higher current densities. By using this, more hydrogen per unit can be produced, decreasing the total cost of the hydrogen produced. As well as this, the new cell topology shows better values of efficiency and therefore will improve the value of operation costs.
To increase electrical efficiency, new power electronics have been designed, based on IGBTs with the capability of working properly and with good efficiency coupled to renewable energy sources. This will improve efficiency during operation and therefore decrease the operation costs.
A new BOP has been designed which includes all the components of a MW electrolyser in the same container. It will decrease costs during the erection and commissioning of the electrolyser and will therefore provide a more competitive unit. A new control system has also been validated in order to work properly alongside renewable energy.
Field-testing has been carried out with successful results. The main goal has been to test the standard market sized electrolyser (1600 mm of membrane diameter) in order to pave the way for future commercialisation. The electrolyser has been working properly at double current density showing good values of V/cell and gas purities.
Much work has been carried out in order to aid market preparation and dissemination. The Regulation Code and Standards (RCS) to put an electrolyser in the market have been analysed. A cost assessment has been done, showing an overall cost reduction of 30% in comparison with the technology at the beginning of the project. A life cycle assessment (LCA) has also been done, showing that the new technology is less harmful in terms of environmental performance.
To summarize, the project has been success on testing a new cell topology with 70% stack efficiency, design a new BOP electrolyser with a capacity of 2.98 t/d and with a global cost of much less than the FCH2-JU objective for 2020 of 2M€/(t/d).
As regards the exploitation of the results, the project has a well oriented market approach with the leadership of IHT. These big units producing hydrogen at high pressure (33 bar) could be used to produce large amounts of hydrogen for power-to-gas applications, helping the hydrogen fuel cell vehicles deployment or for classical industrial applications. Therefore, they can have a direct application and market once the project has finished.
Finally, the different improvements achieved during the project (cell topology, power electronics, BOP, control system) could be directly integrated in the IHT technology, increasing their competitiveness and broadening their potential possibilities in the different short-term hydrogen markets. In this regard, the project has been working on building strong business alliances between partners which will make easier the future technology exploitation.
Project Context and Objectives:
Context and previous analysis
An inherent feature of renewable resources is that electricity generation cannot be fully forecasted and does not usually coincide with the demand curve. As penetration of renewable energies increases, current grid code requirements become stricter and not only they find deviations from predictions but also they are more demanding of the reactive behaviour of wind farms. Hence, a way to store energy is foreseen to be needed when the percentage of renewable electricity share is high in order to help managing the grid. Enabling a certain storage capacity within the wind farms would help to reducing the gap between the generation and the demand curve, as well as damping abrupt variations of the wind power generation. There are various possibilities for the storage of electricity such as pumping by means of hydro power plants, batteries, compressed air energy storage (CAES), flywheels, and hydrogen. Among these, pumping is the most frequently used. And also although less frequently, the energy is also commonly stored in batteries, but their size requirement is a costly drawback. Under these circumstances, hydrogen constitutes a competitive storage technology, either for round-trip electricity production, for co-production of hydrogen as an alternative fuel or to be injected to gas grids. This option relies completely on a robust and cost efficient electrolyser technology of MW scale.
There are mainly two electrolyser technologies available today: polymeric and alkaline. Polymeric electrolysers, although quite efficient, are limited to power stack of the order of kWs to hundreds of kWs, whereas alkaline electrolysers stack range between a few kilowatts to several megawatts. Wind farms are in the last range (typically 20-50 MW), and nowadays, there are only a few electrolyser manufacturers with the know-how and the capability of manufacturing such high capacity electrolysis units. On the other hand, electrolysis units that are able to operate at high pressure show many advantages over atmospheric ones, such as savings in the compression unit downstream of the electrolyser and faster reactive capacity of the stack and enabling longer standby times (required for intermittent operation and low capacity factor).
Although the theoretical efficiency of electrolysers can never be reached because the process deviates from idealness due to thermodynamic losses as well as material limitations, the current electrolyser efficiencies generally range between 52% to 70% (HHV) for both alkaline and polymeric electrolyser, leaving a big potential for improvement. Another important point to be analysed and studied is that nowadays there is no available technology developed for partial load or intermittent operations within that range of electrolysis power. New developments are necessary to match renewable electricity production with its intermittent nature. Current technologies must be redesigned to achieve higher efficiencies and to be reliable, robust and competitive with capacity factors lower than 25%.
Objectives and the Elygrid Consortium
Taking into account the previously described scenario and potential market niches, ELYGRID Project aimed at contributing to the reduction of the total cost of hydrogen produced via electrolysis coupled to renewable energy sources, namely wind turbines, and focusing on megawatt size electrolysers (from 0,5 MW and up). Work has been aimed to the improvement of the efficiency and the reduction of total cost of ownership, through design tasks, modelling and development works and demonstrative tests of the technology in a market diameter scale facility. The baseline used as reference within the Elygrid project corresponds to the state of art alkaline electrolyser from IHT, partner in the project, being a manufacturer that nowadays has installed worldwide and running MW capacity alkaline electrolysers for hydrogen production.
Basically, a MWAE is composed of 3 subsystems: cell stack, power electronics and balance of plant (BOP). Current designs are suited for more than 97% factor capacity and to run most of the time at full load . To match the intermittent nature of renewable energy sources, and specifically wind energy, a re-design must be made. The re design and test efforts oriented to obtain incremental improvements on the design were focused on these three different areas. To achieve the global goal stated before, the focus on the three different sections of the electrolyser system has facilitated being able to target a broad list of objectives, previously defined on the Elygrid Description of Work, which is summarised below:
O.1 Definition of new operation conditions of the electrolyser for improvements in performance and efficiency.
O.2 Increase the current density by a factor of two (relative to baseline electrolyser), maintaining the same diameter stack, hence doubling the nominal production of the SoA electrolyser.
O.3 Development and study of new diaphragm/membrane materials, attaining controlled porosity, sufficient mechanical strength and low cost, capable for elevated operation temperature and increased electrolyte concentration.
O.4 Improvement of stack materials and components in order to increase electrolyser efficiency (by reducing cell voltage), reliability and durability, supported by advanced modelling.
O.5 Identification of the limiting factors for the membrane functionality (like aging, contamination, etc...) by means of micro-structural analysis (SEM, TEM, EPMA).
O.6 Reduce the cell voltage (current 1.9 V/cell to 1.6 V/cell target) by raising the operating temperature up to 100 °C and reducing the resistance of the cell assembly (membrane, electrodes, and electrolyte). The objective is to achieve an increase of the stack efficiency by +10%.
O.7 Specify process and instrumentation diagrams -P&I D- of a 6 MW electrolyser.
O.8 Identify technical improvements related to the Balance of Plant (BOP) which represents approximately 16% total alkaline electrolyser capital cost (cost reduction estimated: 5% of the total capital cost).
O.9 Re-design power electronics, less sensible to the electrical grid parameters, and study and optimize power electronics considering factors like efficiency, harmonics and reliability (electricity energy consumption reduction 10%).
O.10 Design, develop and test the concept of converters for 3.300 A DC and 800 V.
O.11 Field test of new stack built according to the membrane and stack developments.
O.12 Identification of technological market and local value-chain suppliers.
O.13 Assess total investment reduction cost of 25% (BOP cost reduction 5%, stack cost reduction 20%).
O.14 Outreach, social awareness and promotion of alkaline electrolysis coupled with renewable energy sources through demonstration projects, field testing and integration.
O.15 Shed light on RCS aspects for electrolyser technology to facilitate commercialization worldwide.
O.16 Comparative Life Cycle Assessment (LCA) studies carried out according to the practice guidance developed by the FCH JU.
This objectives’ list was already pointed out in the DoW taking into account the capabilities of the consortium behind ELYGRID project, which consists of a complementary team of academic, research and industrial partners with know-how in renewable energies, electrolysis, membrane separators design and characterization and energy demand management, from which several synergies have been possible, helping to the fulfilment of the project objectives through the tasks defined to reach them.
Fundación para el desarrollo de las nuevas tecnologías del Hidrógeno en Aragón (Foundation for Hydrogen in Aragón or FHA [Spain]) has carried out, among other tasks, the coordination of the Elygrid project. FHA is a private non-for-profit research centre promoted by the regional government and more than 60 public and private stakeholders. FHA has also been a key partner for the BOP development and design tasks, together with the field tests carried out at full scale electrolyser’s diameter, thanks to the already installed scalable electrolyser (1.6 m diameter, operation pressure >30 barg) which has been available for stack testing within the project.
Industrie Haute Technologie (IHT [Switzerland]) is a company with more than 40 years of experience in the electrolysers’ manufacturing field. Its role in the consortium has been related with stack design, manufacturing and testing (at pilot scale and full diameter stack) and with assessment and monitoring of costs for the new developments together with market preparation.
In order to join efforts at European level and in tasks related to membrane development, two entities (VITO [Belgium] and EMPA [Switzerland]) have been focused on designing, testing and characterizing new membrane separators materials for the electrolysis cell.
EMPA, Swiss Federal Laboratories for Materials Science and Technology, is a fully independent public research institution with 800 employees. The Laboratory “Hydrogen & Energy” has been involved in development and study of new diaphragm/membrane materials, as well as in the identification of the limiting factors for the membrane functionality like aging, contamination etc. by means of micro-structural analysis techniques.
VITO (Flemish Institute for Technological Research) implements client-driven research projects and develops innovative products and processes. Around 15 years ago VITO developed the ZIRFON® composite separator, which showed very high potential for solving the drawbacks of other alternatives to traditional membranes, but its use is limited to certain applications, due to the limited mechanical properties. VITO has been working on developing better separators based on ZIRFON® along on characterization of them.
Instrumentación y Componentes (INYCOM [Spain]) was created in 1982 with the aim of delivering services and solutions on IT, analytical technology, electronics and electromedicine. Nowadays, besides keeping its original orientation, a consolidated R&D group in the company has acquired valuable experience in the fields of instrumentation and control of industrial systems, along with the development of products in distributed power systems and smart grid solutions. INYCOM has provided the consortium the know-how on controlling and monitoring the electrolyser, while developing an improved control system for field testing.
Ingeteam (INGETEAM [Spain]) has worked on the specifications, design and testing of new power electronics systems which could integrate grid and electrolyser in a more efficient manner. Ingeteam provides application engineering, including turnkey projects on electrical equipment. Along the years, the company has also specialized on design and building electrical equipment, executing high and low voltage installations, with scales ranging from kW to megawatt, in power generation plants or in marine and railway traction applications, among others.
LAPESA [Spain] is the head of a group of companies, experts on manufacturing and marketing products focused on pressure tanks and pressure equipment. The R&D group, located in Zaragoza, has worked on the mechanical redesign of main parts of the electrolyser, in order to update the materials’ usage aiming at lowering the costs. Besides, the experience of LAPESA has been very valuable in the development of the RCS studies that were developed in the project.
The sections IEK 3 and IEK STE of the Institute of Energy and Climate Research with in total about 150 employees are part of the Forschungszentrum Jülich. (FZJ [Germany]). The experience on static simulation of alkaline electrolysis, stack simulation, life cycle assessment of new technologies and energy systems modeling have been a key part of FZJ commitment in the development of dynamic models of the electrolyser integrated with RE along with the LCA studies carried out.
As far as market studies and possibilities for new markets’ strategies, Areva Stockage d’Energie (AREVA [France]) has provided to the consortium its experience on sustainable energy solutions assessment, energy management and fuel cell and electrolyser systems development and market segmentation.
CEA-LITEN (CEA [France]) is the Laboratory of Innovations for New Energies Technologies from CEA, French Governmental Research Organization devoted to both fundamental and industrial R&D in the field of energy, information and health technologies and defense. It addresses several renewable energy applications including hydrogen production, storage and fuel cells (SOFC and PEFC). Having already a good experience in electrolysis techno economical evaluation and in testing and modeling high temperature electrolysis and PEM electrolysis cell and stacks, CEA-Liten has been involved in modeling at cell level, and in developing a techno-economic analysis.
Project Results:
1. Power Electronics
Aligned with the objectives of redesigning the power electronics to assure an efficient connection between electrolyser and renewable energy grids, Ingeteam developed the tasks required to design the power electronics module, develop a concept converter and testing it as a concept prove previous to commercialization. As grid and load specifications had to be defined in the first steps of the project, the strategy followed required:
• Set of specifications regarding the integration of the baseline electrolyser with RE energies
• Development/construction/testing of a power module as defined
• Conceptual design of the power module for the electrolyser working at double current density than the baseline
Starting with the proper characterization from an electrical point of view of an alkaline electrolyser and according to the empirical data measured with the base-line system available at the FHA premises, Ingeteam created a complete electrical behavioural model to simulate the load to be fed by the converter, considering its dynamics, restrictions, operational range and the rest of the specifications of the electrolyser.
On other hand, from the wide analysis of possible topologies to use as interface between the grid and the electrolyser defined in previous stages of the investigation, only three of those were analysed here in depth.
• The first design proposed is formed by a classical converter and has been oriented to an industrial scenario where grid conditions are supposed to be stable and special connection specifications (flicker and LVRT) neglected.
• The two new remaining designs based on IGBTs have been designed for a more restrictive scenario generally related to renewable energies integration where particular grid conditions and restrictions have been considered for the design process.
Simulation results show that the first topology presents the best efficiency but has some drawbacks as its power quality and grid stability dependency. The two other topologies present a slightly worse efficiency compared to the previous one but both offer better power quality and response to grid instabilities.
The second converter design was selected as the one with the best balance between electrical features and cost, number of elements, simplicity and volume, so this topology shall be considered as the starting point for the future development of a prototype.
Once the adequate power electronic topology oriented to the hydrogen production via alkaline electrolysers has been selected, and its design validated through simulation, the commissioning of the converter prototype was carried out.
A test bench to validate the prototype was also commissioned which was constructed so that it might test two power stacks set in parallel. The power module design was tested using the standard battery of tests and checklists for other products of Ingeteam (including temperature rise, insulation, cooling circuit, power stack elements,…). The results have met all quality standards and accordingly the design and prototype has received the internal approval and readiness check-up for pre-manufacturing.
Once the power module was accepted as valid, an advanced power conversion unit for advanced electrolysers was designed. A new conceptual power conversion stage adequate to feed the latest generation of the advanced alkaline electrolyser was considered. The electrolysis stack marked as objective has to be able to work with the current densities in the range of the FCH-JU objectives maintaining the same number of cells.
The modular design, on which the selected power stack design is based, makes it possible to design a “Custom-Made Configuration” for each case and application. One of the main advantages of the selected and built power stack was its modularity in terms of power. Besides, this new design achieves efficiency improvements round 10% taking into account the operation profile of the electrolyser. This asset represents several advantages not only for the developers and suppliers of the solution, that is to say, Ingeteam, but also for the purpose of this project. On the one hand, the fact that the design is modular enables an obtainable and to a certain extent “easy” solution to account for any, present and near-future, further material and mechanical advances of said Electrolysers. And on the other hand, it renders the power stage apt for other market applications such as the wind power sector.
It should be carefully analysed how many power stacks in parallel should be used to handle the specified values of current. The scalability of the power stack solution could be obtained through the parallel connection of multiple power modules. Parallel connected power modules offer power scalability advantages but request outstanding precision at the time of synchronizing the current and voltage measurements.
Ingeteam has an extensive experience and expertise in the field of power converters in which parallel connected power modules are used. The synchronization between the converter control unit and the power modules can thus be considered as a proven solution within Ingeteam products.
2. Membrane development and tests
Membrane development within Elygrid project was mainly carried out by VITO and EMPA. Two different approaches can be described.
First, a novel one-to-one replacement for the baseline previous technology used in the MW electrolysers by IHT, which additionally leads to improved cell efficiency, had to be developed. In the first design considered for the Elygrid project, new membranes topologies were compressed to fit the distance between the electrodes. The first new concept to be developed had to be designed and tested to fit in the same cell gap.
On the other hand, a lower ionic resistance membrane, in the range of the comparatively commercial membranes was highly desirable for reaching the goal of higher cell efficiency.
The development of thinner membranes has to be related with changes in the original baseline cell configuration, in order to assure a proper fitting and contact between membrane separators, electrodes and bipolar plates. The use of thinner membranes aimed also at achieving lower resistances and better cell efficiency.
For each one of the paths described above, several samples were developed, being compared and described after characterization battery tests documented from the beginning of the project (ionic resistance, pore size, permeability, corrosion resistance, bubble point measurements). The most promising ones after this screening step were tested at lab scale and then the selection continued to pilot scale at the real operating conditions, in small diameter electrolysers, before selecting which one was better suited to be built at full size and installed (1600 mm diameter) for the field experiments. Cell voltage and efficiency was also compared to reference cases (previous membrane and commercial membranes).
Path 1: Composite and multilayer membrane separators (EMPA)
The choice of materials for separator production was based mainly on chemical stability, due to the severe desired operating conditions (when electrolyte conductivity is near its maximum). Synthetic and natural materials were investigated as fillers while polymer materials felts and fabrics were decided to be used as support to provide the necessary thickness.
Corrosion experiments were carried out to provide input about the compatibility of the materials in a KOH medium, after 8000 hours in 25% KOH(aq) at 85°C. The results showed a significant dissolution of mineral materials, including the reference, while synthetic materials showed lower corrosion rates.
Investigations on the influence of different filler types, PSF concentrations and filler to binder ratios on the final separator material were carried out. The resistance of each separator has been measured in U/I curves and compared to commercial separators from IHT. The reference materials abbreviated as A1, A2, A3 and A4 have shown the differences in ionic resistance, as possible to see from U/I characteristics in, in relation to their porosities. The lowest ionic resistance has been achieved for sample A4.
Path 1: Dual layer concept membrane separators (VITO)
VITO proposed a dual-layer concept in which the first layer act as a distance holder to fill up the open space, whereas the coated separator layer needs to fulfil all tasks expected from a separator (high BP, low resistance,). First, all the candidates support materials were characterized for their ionic resistance, resulting in a better behaviour for the spacer fabrics due to their open structure.
In a second stage, VITO developed different configurations of supports and coatings by changing the thickness of the final solution and assessing the main physico-chemical properties. It was significant the efforts carried out to find the best support material with a good performance in order to work in the operation conditions at 30% KOH, 80ºC and 30 bar. Besides, all the permeabilities and bubble point of all the membranes were compliant and compared with those taken as reference.
Path 2: Asymmetric membranes (EMPA)
On the basis of experiments, thermodynamic modelling and membrane leaching experiments, Mat 2 and Mat 3 were selected as the materials of choice to continue developing improved membranes. Mat 2 due to its price and patent-free restrictions became a more attractive alternative, besides its low resistivity and low permeability to gases.
The membranes developed can be categorized in three different classes, depending on the microstructure modification technique. The thinner membranes developed within “Path 2” were compared in their characterization and behaviour against a reference commercial membrane and as the reference behaviour of previous technology membranes.
The resistivity of the new developed membranes was in any case lower than the commercial reference material and a bubble point pressure characteristic of each of the methods used, which will be used as selection method to be tested in the electrolysis lab scale cell.
Path 2: Symmetric membranes (VITO)
New membranes were developed by VITO via phase inversion process. The separators represents more symmetrical concept by means of surface similarity, not being its entire microstructure identical. The developed membranes were produced aiming at having three different classes or variants, taking into account different combinations of permeability, bubble point and pore size distribution.
Especially resistivity has been drastically improved when compared to commercial reference membrane (and of course compared with previous technology reference membrane). Simultaneously bp pressure show better (or much better) chacacteristics.
Thin membranes were tested in an electrolysis setup at high temperature and pressure, based on the preselection criteria. The list of specimens was narrowed down to membranes representing the extreme parameters (two by VITO and three by EMPA) having different combinations of bubble point, resistivity and permeability in order to assess the effects of these characteristics in the gas purities and the voltage. Additionally, the commercial reference material was tested under the same experimental conditions.
From this comparison it is clear that all newly developed membranes have performed better that SoA separator which had been previously used by IHT. The lowest voltage drops have been obtained for B44 and V27 membranes, which have almost identical I-V characteristics. The calculation of the gas production increase for the same voltage between commercial membranes and B44/V27 results in a 13% yield.
The in-situ measurements however do not exactly represent the trend reported from the ex-situ zero-bias resistivity measurements, carried out during the preselection stage. Since at higher current densities, the concentration overpotential dominate and because used electrodes as well as the cell assembly are identical, it can be hypothesized that the reason of the results discrepancy is related to either:
• Dynamic conditions during the electrolysis: the interface between the electrode and the membrane indicating different hydrophobic/hydrophilic properties, which are not taken into account during the ex-situ static measurements
• measurement error of the zero-bias resistivity, which is more sensitive to specimens of a smaller scale
• an overlap of both effects
Electrochemical tests of selected separators
During the project mainly three electrolysis test setups have been employed. The main differences, beside the operating pressure and temperature, are the electrodes, which were installed into the electrolysis cell. Their short description could be summarised as follows:
• Ambient temperature/pressure electrolysis cell with an acronym: Electra 2. This setup has been constructed within ELYGRID projects and established the basic results for the modelling. This setup was equipped with electrodes supplied by IHT. The diameter of the electrodes amounted to 46 mm.
• High pressure high temperature electrolyser working in the stack configuration with an acronym: Voltiana. This setup was purchased from H2 Nitidor (Italy) and used during the last stage of the project. The electrodes incorporated into the Voltiana stack are sand-blasted Ni meshes, having 113 mm diameter. The electrochemical tests were based on a 7-cell stack configuration.
• Ambient temperature/pressure electrolysis cell with an acronym: Electra 3. Electra 3 has been constructed during the last year of the project as an improvement of the Electra 2 design. The cell employs 2 hot wire-cut coarse Ni electrodes with a diameter of 25 mm.
3. Balance of plant optimization
The goals of the project related to BOP was related to identification of improvements that could derive in a cost reduction of the 5% of the CAPEX. The tasks on BOP optimization have also taken into account the OPEX, in order to find a compromise in the final TCO.
Capital cost reduction was studied as objective through
• Mechanical re design (reduce the use of materials)
• BOM review
• Commissioning costs
Aligned with the European scope of the project, the selected code for the redesign of the main mechanical components of the BOP was EN 13445, which is the European code for the construction of unfired pressure equipment and it is harmonized with the Pressure Equipment Directive (97/23/EC). A review of the code design was of key importance in order to systematize the design process of the equipment to develop, including materials quality definition, safety factors, test groups and coefficients. LAPESA, applying the aforementioned design code, proceed to develop the review of the classic design of head-plates, tie rods and supporting feet of stack and gas separators. The mechanical redesign of gas separator and mechanical parts of the electrolyser was done for 37 bar, 120°C and 1.6m (cell’s diameter).
The design of heads, bolts and studs and head-plates showed to be only dependant on cell diameter and pressure, not length (meaning that the final number of cells, which provides a stack length influences only the number of supports)
The mechanical redesign done to gas separators, head plates, tie rods and feet have showed a significant opportunity to reduce costs and the manufacturing process has been updated following the standard used nowadays. This new mechanical design, developed in accordance with the standard EN13445 shows that an improvement of the cost reduction in the gas separators of 10% (30% decrease in weight) and in the other components of 5% (10% decrease in weight) could be achieved.
In accordance with the cost breakdown for the reference unit (3,5 MW) provided by IHT, a 14% of CAPEX is due to on-site works during the erection and commissioning of the electrolyser. It means that this cost is as significant as the Power electronics or total BOP costs. Therefore, it can be concluded that, at least for units as the reference one, the reduction of the commissioning costs is a key issue to be addressed.
In order to reduce the on-site works, a modular design of the system is proposed. Several tasks are being developed to achieve a modular design:
• IPR and market analysis
• Container definition
• Equipment distribution inside the container
• RCS assessment
• Equipment design and specifications
• P&ID and Bill of Material
• Risk analysis (related to P&I D and control strategies definition)
• 3D Design
After assessing the adequacy of pursuing a modular and containerized design, before starting with the bill of materials review and redesigning the process and instrumentation needed, other studies were carried out regarding the container definition. FHa developed a calculation tool with which preliminary weight and equipment calculations were done to fit the whole electrolyser system in a standard container. Continuing the results from the sizing tool and the transport cost study, an analysis of distribution possibilities was done, revealing that the assembly operations could be also divided into two principal tasks: stack assembly and BOP assembly. Indeed, this differentiation would also allow executing the main assembly tasks in parallel, obtaining also a better work flow distribution in the workshop.
Once the stack power and expected behaviour (determined also according to the test field results of the possible new membranes) the rest of the BOP components were also specified according to a P&I diagram. This P&I was the subject of several reviews, mainly related to the safety and risk analysis that was being carried out for each version.
A complete bill of materials was addressed finally, including operating range, materials, models and price for each component, in order to assess a complete design which could be considered as pre-production for a new concept electrolyser system. The complete BOM included components which can be categorized as:
• Pressure equipment (gas liquid separators, heat exchangers, filters, etc)
• Valves (control valves and electro-pneumatic actuators, check valves, pressure relief and safety valves, drains and purges and bypasses operations)
• Field instrumentation (manometers, flowmeters, level transmitters and gas analysers, both normal control instrumentation and safety instrumentation)
• Pumps
Besides the standard BOP, two other auxiliary systems were designed and specified: the demineralised water production module and an external purifying module to decrease the oxygen and water content to use the hydrogen in a fuel cell.
Comparisons of the overall system cost breakdown with the state of art alkaline MW electrolyser is described with detail in the next section, but as a basic comparison to state the fact that the objective of lessening the commissioning and initial costs is being achieved, the gross BOP cost reduction has been of around a 20% when comparing the same basis (e.g. including - or not - peripherals systems, i.e. water production and hydrogen purifier), while if the comparison is made taking into account the hydrogen production (cost per Nm3/h of H2 produced), the cost of the BOP for the Elygrid container design would be half the state of art BOP cost. It is important to mention that, in spite of the containerized nature of the new design, packaging costs are expected to be not much higher than those of the state of art BOP.
Due to onsite commisioning personnel costs, transportation and logistics costs involved in the erection of an electrolysis plant, several improvements were studied in order to design a compact plant. This new design involves the following advantages:
• Transport costs reduction. BOP container is now standard size
• More space within the container, facilitating maintenance
• Greater flexibility to increase the electrolyser power
• Lower reparation cost in case of an equipment failure
The auxiliary modules (water deionization and hydrogen purification) are designed in 10’ containers. These modules could be (optional) installed next to the stack and the BOP container. Hydrogen purification module is a flexible module, it can purify up to 2200 Nm3/hf hydrogen. It’s situated downstream the BOP container. It needs N2, water and power supplies. Water demineralisation unit produces 2000 l/h of water with conductivity less than 1µS/cm.
The BOP module is fitted in a 40’ container. Priority has been given to the assembly and maintenance operations. It has been designed in order to facilitate the work inside the container. Also the worker would have access from different points, letting do the maintenance in pairs, according to the ISO 15916 standards.
The main (bigger) components of the BOP were distributed in order to keep balanced the mass centre of the container. The free space was conceived to be used for control valves panel and the gas analysis cabinet. In order to facilitate the main assembly operations, valve panels are pre-assembled before being mounted in their final position inside the container.
A free space has been created to let the workers get in and calibrate gas analysers, replace gas bottles, calibrate flow sensor, etc. All the process conections with other modules are in the back-side of the main container. These flanges are welded to the back wall in order to increase the mechanical resistance of the structure.
As final conclusions, these two achievements should be pointed out:
• New BOM for the optimized BOP: the complete BOM has been reviewed, starting with the baseline, redesigning the processes and process lines, in order to seek a cost reduction while keeping or reaching better functionality and safety characteristics. The BOM has been also updated in term of costs, dimensions and specification sheets. The new system has been also extensively analysed from the safety point of view, being the subject of a qualitative and a semi-quantitative risk assessment studies, being designed under the pertinent RCS and being under an ATEX analysis. On the other hand, and together with the updated control system, a complete operation and maintenance manual has been developed for the new design. The cost reduction has been decreased dramatically as explained in the document.
• Modularity: allows decreasing costs executing most of the assembly operations at the manufacturer workshop, reducing the onsite works at the client facilities. Easing the maintenance operations has been also a key factor to take into account in the modular design. Not only the standard BOP (compared to SoA) elements have been designed and completed in a 3Dview, but also some peripherals modules, like demineralized water production and hydrogen purification unit.
4. Improved control system
The main goal was to define a new control system with improved functionalities and stable enough to be remotely operated coupled to RE. In the first steps, Inycom made a deep analysis of the original control functionality and performance identifying those areas which needed to be improved to reduce OPEX and increase the automation level of the process. During the development of the new control, the join work of Inycom and FHA has been a cornerstone to define a new control strategy, implement new operating states, establish the transition conditions between states and define new alarms and warnings.
All the operation states and their transitions were redefined in collaboration with FHA trying to automate to the maximum each process, aiming to reduce dead times and the need of human interaction. It was detected that there were several actions that requested the operator’s approval or even in some cases, the operator had to control part of the process manually. In the new control system all those tasks and most of the transitions between states have been automated completely, reducing the time needed to reach the production conditions as well as the time to stop and improving the work of the operators. Additionally, two new operation states have been implemented which increase the functionality and will help to reduce considerably OPEX and transition times.
In this part of the process, the prediction and forecasting models developed by Inycom play an important role. These algorithms are able to estimate the electricity cost 24 h before and the renewable energy production in the same time frame. This allows the system to choose between selling the renewable energy or to start the electrolyser for energy storage. For example, if it is expected that a high electricity price will appear in short time it doesn’t make sense to produce hydrogen therefore, the system will be stopped and when profitable conditions are met, the system will start again producing at full or partial load, depending on the predictions, without having to restart the system from the beginning with the resulting OPEX and time reduction.
The integration of renewable energy resources with the control could allow a better exploitation of the renewable energy produced since depending on the energy demand it can be chosen whether to store energy (if there is overproduction) or to sell that energy to the grid in order to assure the power supply.
Other control improvement has been related to the review of the control loops. After analysing the control of the plant, it was noticed that there were several PID controllers which were not well designed and tuned, and thus they were making the system become inefficient and in some cases not completely stable. This type of control could not predict the disturbances on the system and the PID controller only took into account the difference between the reference and the measured output.
The new control system, a feedforward control combined with feedback, has been implemented. With the feedforward control, the disturbances and changes of the system are accounted before they have time to affect the system. This fact can be especially beneficial for slow systems in which it takes a long time to observe changes in the measurement. Therefore, the feedforward control is used to give predictive information to the PIDs. The value for the feedforward is calculated by designing operation models which consider the value in real-time of the associated process variables and actuators. Feedforward models have been developed for the main components to control, resulting on a control system that copes much better with the process disturbances that can affect the stability of the system.
Finally, it has to be pointed out that the control improvements not only have been designed but also developed and tested with the 1600 mm electrolyser at FHA premises. A tailored web interface has been developed to monitor and control the process remotely. It has been done taken into account the operators’ needs, so that they can access easily to all the information they need. It can be accessed from any browser and from any device. This fact would help to OPEX reduction as the use could have people on call instead of present on location, which is cheaper. It will also reduce OPEX costs as one person will be able to be on call for multiple systems on multiple locations, instead of having one person monitoring each installation.
To sum up, the following tasks have been carried out in order to develop an enhanced and efficient control system of the electrolyser:
• Development along with FHA of a new control strategy for an alkaline electrolyser, including new operation states, warnings, alarms and operating modes coupled to RES.
• Selection and installation of hardware for the experimental plant. The installed hardware was chosen due to the high performance of its CPU, the availability of standard programming languages and the possibility of adding more I/O modules for a future expansion.
• On-site implementation of the control system ending up with a totally working product to control the alkaline electrolyser.
• Design of a control system (hardware and algorithms) scalable to MW electrolysis, tuning of the control system in the experimental plant at FHA facilities.
• Development of an intuitive user interface to monitor and configure the process on site or remotely.
• The design of the control system has been made keeping in mind the objective of decreasing OPEX by adding the possibility of controlling the system remotely, developing new alarms and designing new PIDs with feed forward control in order to obtain a much more stable and safe system.
5 System modelling and simulation integrated with RE
The rapidly increasing renewable wind and solar power capacities in European countries form the major background of current electrolyser development. This leads to increased shares of electricity that cannot be used in local distribution grids. In order to provide an economic utilization alternative for such electricity quantities hydrogen can be produced via water electrolysis and serve as a storage medium for renewable energy. The specific advantage is, however, its flexibility with respect to utilization, as it can serve as fuel for transportation, as feedstock for chemical industry and also for reconversion to electricity. The technical and economic viability of such energy pathways must be assessed.
Of particular relevance is the derivation of load profiles that result from the computational comparison of grid load and renewable power feed-in:
Pres = Pgrid - Pre
Pres is the residual power which is positive, if power from conventional generation is required for covering the demand. It is negative during periods of wind power exceeding grid load. Pre is the renewable power and Pgrid the grid load.
Such analyses must be performed on a regional if not local basis as the potential and intermittency of renewable power feed-in as well as the potential for renewable power generation installations are strongly dependent on their location. In this work the analysis is carried out for a location in Germany. As part of an ongoing PhD thesis at IEK-3 and outside of the Elygrid project, a regionalized model is being developed that allows the determination of time-dependent profiles of grid load and renewable power feed-in on a municipality (city) level. The clear focus here is at present on wind power which bears the largest potential for renewable energy production in Germany. For the purpose of the project a suitable data set had to be identified.
The requirements where set as follows: in order to ensure high annual load hours the local grid to be selected should provide:
• low grid load
• high potential for renewable power capacity.
• options of nearby hydrogen storage preferably in salt caverns
In accordance with these requirements the municipality of Friedeburg was selected. As it is in a rural region in the North-Western Part of the country it is characterized by low grid load and due to high (average) wind speeds – a high wind power potential. Moreover, salt dome formations are in the vicinity. Among different scenarios that are available for the regionalized IEK 3 model the “40 GW scenario” has been selected assuming a total wind power capacity of 40 GW for Germany. Even though this value is comparable to the actual value for Germany at present it differs from the actual situation as the location of wind power plants follows a cost-optimizing procedure in the model. In contrast, current installations can widely be found in regions with lower wind power potentials, due to the feed-in tariff regulations. The data selected for use in the Elygrid project are thus scenario-related and do not refer to wind power capacity distribution in Germany at present.
For the scenario calculations the negative residual power is being used and now defined as the surplus power Psur
Psur = -Pres -> Pres<0
Psur = 0 -> Pres>=0
Related to the utilization of the surplus power it is clear that 10 MW electrolyser considered here is not able to take-up all the power that is available. Remaining quantities can be provided to the transmission grid or have to be curtailed. This simplified concept of utilizing surplus power has originally been used in the German HYPOS project. In the literature a variety of other operational strategies for electrolysis is available, e.g. on the basis of time-dependent electricity prices. It is assumed here that 50% of the maximum surplus power is transferred to the transmission grid – this parameter is here defined as the lower operational limit of the electrolyser. This option is preferred over other alternatives as the greenhouse gas reduction effect is greater when conventional power production is substituted. Electric power that exceeds the 50% share is available for electrolysis. If also maximum electrolysis power is covered electric power must be curtailed or used otherwise, e.g. for power to heat applications. For visualization, an installed electrolysis power of 30 MW has been assumed. However, the scenario calculations refer to a nominal electrolysis power of the designed range [up to 10 MW]. The lower limit of electrolysis power related to the maximum surplus power is varied for the simulations.
The results shown that hydrogen production quantity, operating hours of hydrogen production and total electric energy uptake are decreasing when the lower operation limit is shifted to higher values. The system efficiency is stable at values ranging from 64 to 65%.
It can be concluded that the setting of the lower operational limit greatly effects the hydrogen yield from renewable surplus power. However, this factor can only be taken into consideration when installed wind power capacity significantly exceeds the grid load. This was given in the example of the Friedeburg municipality that was chosen in the present analysis.
6 Field tests (1600 mm diameter stack)
Field tests are referred to the studies and works done under the Elygrid project for the replacement of the 1600 mm cell stacks erected and commissioned by FHA and IHT. After the erection and commissioning of the first unit on site, tests were carried out to check the behaviour of the new membrane and its working point conditions, comparing with the traditional based membrane.
A first battery of tests was programmed with the new cell blocks. These tests were oriented to obtain a bench of results to compare the operation capabilities of the new cell block with the Elygrid base case.
The new cell topologies tested have increased an 8% the efficiency of the stack at the same current density of the previous technology. The gas purities of the unit are inside the safety range and enable to use the hydrogen in a fuel cell. The results were consistent with the values observed in the small diameter test bench (IHT) for the same current densities.
Several tests were carried out increasing current density, especially to observe the influence on the gas purities, being of special importance the improvements reachable in terms of hydrogen impurity levels on oxygen side.
Long-term tests have been developed, aimed to run the cell block as longer as possible without interruptions. The main results of these tests have been to define the best operation conditions for the new cell topology and assess the effects of the current density, temperatures, flows and gas purities in a broad range of conditions.
The electrolyser at Walqa has been coupled to the renewable energy system (635 kW wind energy and 100 kW photovoltaic), providing good performance in terms of fast reaction in stand-by mode operation, quick changes in loads and good operation of the control system.
7 Techno economic analysis
First, an analysis was made of the techno economic scenarios for the case base electrolyser (SoA, 3.5 MW from IHT). The cost breakdown of the system was provided by IHT. These information allowed at the end of the project to assess the economic impact of each progress achieved, related to the production cost of the system or its performance.
Two simplified scenarios were proposed in order to estimate, in a first approach, the impact of the coupled capital cost and performance factors on the levelled cost of hydrogen and then to compare the reference system with the optimized one. The scenarios were located in Germany, since this country is very proactive on electrolysis solutions for electricity storage and mobility:
• 1st scenario: H2 production & electricity market. In this scenario, the 3.5 MW electrolyser is operated according to the electricity price of the German Day Ahead Epex Spot Market. An optimization was done to define the price threshold under certain conditions above what it is better to shut down the H2 production considering the electricity price and also the involved operating time of the electrolyser.
• 2nd scenario: Green H2 & Wind electricity production. In this scenario, the 3.5 MW electrolyser is directly coupled to a wind farm composed of x turbines of 1 MW. The electricity produced is in priority converted into H2 to be sold as ‘green H2’ and the surplus can be sold to the Day Ahead Epex Spot market with or without incentive price (Premium) for wind electricity.
• 3rd scenario: When presented at the mid-term review, this 2nd scenario was rejected in favour of a ‘Power-to-Gas’ (PtG) scenario, identified by AREVA in charge of the Market studies, as a market segment well suited for the pressurized electrolysis.
H2 production & electricity market
In this scenario, the 3,5 MW electrolyser consumed the electricity purchased on the German Day ahead Epex Spot Market. An optimization was done considering a price threshold above what it is better to shut down the H2 production.
• Main input data:
o German Day ahead Epex Spot for 2010, 2011, 2012
o Fees and subscription cost to attend the market
o German electricity network taxes and charge (lower taxes for a electricity storage application with the removal of the EEG-umlage)
• Variable: market price threshold above what the electrolyser is shut down.
• Criteria of optimization: levelised cost of H2 for a plant life of 20 years and 8% discount rate.
• Simplified approach: no constrain on H2 storage or delivery
As a first result, the figure presents the levelized cost of H2, according to the market price threshold for the electrolyser of reference and for the targeted electrolyser (25% reduction on stack cost, 80% stack efficiency and +10% electrical yields).
In the reference case with high grid taxes (no storage application), the optimum leveled cost of H2 is 4,7 €/kg, obtained for a market price threshold of 55 €/MWh. The targeted electrolyser could reduce this cost to 3,6 €/kg meaning a 22% reduction.
Power to Gas
In the ELYGRID scenario, the PtG system is used to convert the surplus of electricity produced by wind turbines in hydrogen stored in the natural gas network (the concentration limit of H2 in this network will not be taken into account in this study). Considering that the wholesale market price reflects the consumer demand, a threshold price will be fixed above what the renewable electricity is sold to the electricity market and below what this energy is degraded or converted to hydrogen and injected to the gas network.
If today, the investment cost and operating cost of a Wind plant cannot be profitable if the market price is applied without founding, it is obvious that, hydrogen produced and sold to the natural gas network will need as well an incentive price, since 30 €/MWh will not be competitive except for an electricity market price lower than 20 €/MWh (Price of the NG x 0.7 efficiency of the electrolyser). The wind electricity in Germany, when the analysis was made, benefit from an incentive selling price. In fact, the investment and operating cost of a renewable energy plant cannot be profitable if the market price is applied. To promote the development of renewable energy, governments create feed-in tariff and the guaranty to sell the produced energy. In 2012, in order to begin the transition away from fixed price incentives and in order to fit the renewable electricity injection with the consumer demands, the EEG 2012 encourages the direct sale of renewable electricity on the spot market through the introduction of a market premium, equivalent to an additional payment to compensate the difference between the market price and feed-in tariff.
Moreover, the feed-in tariff rate and the management premium are supposed to decrease over time according to a digression schedule. For the needs of the simulation, a fix Premium payment of 50 €/MWh will be considered for the 20 years of plant life
The natural gas in Germany, has a current price of 30 €/MWh. Feed-in-tariffs for biogas exist, fixed at 110 €/MWh for plant of 0.5-5 MW and 60 €/MWh for plant of 5-20 MW. For the scenario, the incentive feed-in tariff of 110 €/MWh will be retained
The power of the wind farm will be fixed at 10 MW. In order to convert all the energy produced, the electrolyzer needs to have an equivalent capacity. This will be the condition for the first simulation and in the second one, the capacity of the electrolyzer will be considered as a parameter of optimization and will vary between 1 and 10 MW.
The second parameter of optimization, similar to both simulations is the values of market price threshold below which RE producer has to use PtG or degrade his production. It will vary in a range of 0-50 €/MWh.
For both simulations, the levelized profit of the system (PV) and the maximum investment cost of the electrolyzer are calculated
• For simulation 1, with the parameter of optimization: ‘market price threshold’:
o S1 reference: 10 MW Wind power plant without PtG
o S1 PtG 10MW: 10 MW Wind power plant with a 10 MW PtG
• For simulation 2, with the additional parameter of optimization: ‘electrolyzer capacity’:
o S2 PtG 1-10MW: 10 MW Wind plant with variable capacity of PtG
o For this simulation in particular, the maximum specific investment will be calculated for different capacity of the PtG system
The results of the different simulations showed that despite favourable hypothesis (reduction in taxes, incentive selling price), in the current electricity market, the period of time with negative or low prices on the electricity market is not long enough to amortize the investment in PtG solution even with the expected improvement aimed in the project.
8 Life Cycle Assessment
The goal of this point is to present an in-depth assessment of environmental impacts induced by the advanced alkaline water electrolysis systems in comparison to state-of-the-art systems. This LCA is compliant to ILCD and therefore also to ISO 14040 , 14044 and FC-HyGuide. Most of the relevant data derive from the partners in the EU research project “ELYGRID”.
Environmental assessments of hydrogen production have been subject in many studies. However, a review paper shows that most of these studies had an exclusive focus on Global Warming Potential (GWP). Little attention has been paid to evaluation of ecological effects of individual alkaline electrolysis constituents. Therefore, modelling of environmental impacts caused by an exchange of membranes was not possible in the past.
Life Cycle Assessment (LCA) is used as method for environmental assessment within this study. LCA involves environmental impacts over the entire lifetime of products or systems. Finally, the main aim of this point is to present key results of the LCA and to assess if the technological advancement of electrolysis systems leads to environmental improvement.
The LCA includes a comparative presentation of the environmental outcomes of three different electrolysis systems. A state-of-the-art of traditional electrolysis system is compared to advanced new cell systems.
• Reference is a state-of-the-art 3.5 MW electrolysis system using conventional membranes (system I).
• The second system (II) includes the advanced membrane instead of the traditional membrane. This system is assessed to evaluate the effects of changes on cell level solely.
• In addition, an advanced system, which is planned for commercial operation, including further Balance of Plant (BOP) improvement (redesign of mechanical components, infrastructure changes) is analyzed (system III)
All three systems within this assessment are compared on the basis of the functional unit. For our assessment the production of 1 kg H2 at 33 bar and 40 °C are considered as functional unit. A technical service life of 20 years is considered for all systems. FC Hy-Guide proposes the subdivision of hydrogen production systems in construction, operation, and end of life.
Two different operation scenarios are analyzed within this assessment. As ecological best case an operation with wind power is considered. On the other hand an operation with electricity grid mix is assessed as worst case. For both cases a nearly year-round operation with only five short stops and start-ups a year is assumed. The prospective real operation will probably have lower full-load hours, but is not clearly quantifiable by now.
Results for the selected environmental impact categories applied on the three system types and two scenarios as well as related to the functional unit of 1 kg H2 are defined. Beside absolute values of the entire systems, shares on construction, operation, and disposal are taken into account.
Potential Impact:
As ELYGRID project specifically has addressed the coupling of high pressure and high capacity alkaline electrolyser with wind energy, it is expected that the results from ELYGRID will have a considerable impact beyond the geographical and time scopes of the project, contributing to advances in answers related to the new typologies of electrolytic hydrogen adapted to maximum penetration of renewable energies, especially wind energy.
Application of the results should not only benefit the EU, but could specially contribute to soften the serious environmental problems coming from developing countries which need new clean energy technologies to supply the electricity needed to support their socio-economic development, compatible with the preservation of the environment. Besides, the improvements have been technically assessed on different levels (membrane, cell, balance of plant, control) but also on other transversal matters (market analysis, RCS and LCA) which also contribute to expecting a wide diversity of impacts at different levels.
The development of the ELYGRID project, through the individual improvements, tests, designs and analysis done, is expected to derive in some impacts at short-term, while the general approach and strategy followed shall have repercussion on a mid/long-term level.
Among the short-term impacts, the following must be noted:
• Reduce H2 production cost from electrolysis with RES to approach the objectives of the FCH JU.
• Efficiency improvements of an alkaline electrolysis cell in high power pressurized electrolysers for mass production of hydrogen from RES.
• Prototype testing to verify and qualify the technology and raise public acceptance.
• International relevance.
• Demonstrate the technology in order to favour new projects, developments, products and services.
• Consolidate the strategy for alkaline electrolysis technology deployment, including RCS and LCA aspects.
• Generate confidence in electrolysis as an efficient technology to produce electricity and hydrogen from RES.
• Promote technological knowledge in RES sector, especially wind energy, for replications.
After the results and experience obtained in the Elygrid project, and thanks to the achievement of the proposed objectives and results, some steps have been made to pave the way to the mid- and long-term impacts:
• Saving on fossil fuels in electric power generation, making it less vulnerable to future problems in the supply of these resources
• Decrease in the high levels of pollution stemming from the existing power plants
• Expansion of the European renewable energy industries beyond its borders
• To contribute to improve energy efficiency
• To support renewable energy markets, by providing electric grids infrastructure with energy storage capacity, suitable for a maximum penetration of variable and intermittent RES, providing grid services.
• To contribute to satisfy electrical energy demand in a self-sufficient cost-effective way, by providing abundant, clean, secure and affordable energy, whilst simultaneously achieving substantial reductions in greenhouse gas emissions to mitigate the potentially serious consequences of climate change.
• To promote the security of energy supplies for the European Union
• Contribute to the development of more flexible, reliable and cost-effective energy storage solutions that will support the progressive introduction of RES technologies
The participants in the Consortium are currently, or have been in the past, involved in numerous projects, European as well as national and regional. Moreover, they have been involved in the different areas of industry and know-how with which the project has a direct relation: alkaline electrolysers and renewable energies.
European dimension
The project results are expected also to contribute to the development of policies in the areas of energy efficiency, promotion of renewable energies, and distributed generation related to production of hydrogen from alkaline electrolysis. LCA has been carried out in order to compare and establish that the proposed integrated solutions are ecologically suited to compete with other more conventional commercial alternatives under a reasonable set of accepted environmental impact indicators. Setting up an industrial project with international scope, to get technical data for RSC aspects and legislation development, has to favour mechanisms to motivate public bodies towards hydrogen production from renewable energies, and help the implementation of green certificates, investment aid, tax exemptions or reductions, tax refunds and direct price support schemes. From this point on, technology maturation will be faster due to the creation of an incipient market in a natural way.
The ELYGRID project has assessed the regulations, codes and standards at European level in order to check if potential policies gaps could block the commercialization of these electrolysers in the short term. All the analysis of the different directives has shown that the manufacturers have all the information in an EU policy framework level in order to commercialize an electrolyser.
In the middle and long term, European and national support mechanisms to incentive hydrogen production from RES have to be created. These incentive mechanisms could include green certificates, investment aid, tax exemptions or reductions, tax refunds and direct price support schemes, and should consider the external costs of electricity produced from non-renewable energy sources and the impact of public support granted to electricity production normally used to encourage the development of renewable energies within the internal electricity market.
ELYGRID project has a triple European character. First, due to the diversity of European countries which are involved. Secondly, the project is applicable to all member countries of the European Union, since issues associated with clean electric power generation and energy storage are clearly beyond borders and so are the benefits arising from the realization of the project. Third, the expected results affect several areas which constitute important goals which are central to the European Union policies such as promoting environmental protection and energy saving, fighting climate change and maximizing the use of renewable energy and the independence of fossil fuels.
Broad market introduction, however, is often hampered by high initial costs and thus insufficient customer demand. Action at the European level is expected to be required to create markets of sufficient size to bring down the cost of better environmental performance technologies. In any case, the market orientation of the project has proved to be very useful to provide a continuous analysis of costs for each technology and development proposed. Having several industrial partners being part of the consortium has totally permitted keeping this orientation along the duration of the project.
The Green Paper – Towards a secure, sustainable and competitive European energy network – stablishes a new approach to energy network development, considering that it should become a central issue when implementing energy policy. The 20-20-20 objectives have to be implemented in an effective manner, and it should be addressed through programmes relating to public and private sectors. The paper also states that European research should direct its work to the following key drivers:
• the integration of renewable energy sources in the network;
• the transport of energy from resource-rich areas to consumption centres;
• the use of technologies for the decentralisation of energy production and intelligent networks;
• the use of energy coming from offshore wind farms
• the development of technologies for the transport and storage of CO2.
At this level, ELYGRID could be considered also has a step towards these objectives, as far as the research has provided useful to develop more know-how and new technologies and designs that could be implemented in the near future to provide grid services.
Commercial impact
During ELYGRID project several market studies have been analysed in order to provide insight of the commercial possibilities of the overall system, at the studied scale corresponding to the SoA electrolyser and the Elygrid design.
The studies started with a reminder of why energy storage is an essential part of the deployment of renewable energies. As renewables are deployed, there will be more variability and intermittency in power generation, resulting in an increased need for flexibility to both smooth renewable power flows and maintain a stable grid. Different possibilities are envisioned to provide the needed flexibility, such as:
• Grid interconnections (power, heat, cold, gas): improvements of T&D meshing to mitigate the local variability of intermitent renewables output (North Sea Supergrid, Medgrid, Tres Amigas, etc)
• Flexible fossil energy sources: oil or gas fired single cycle combustion turbines. Depending on geography and hydrography: hydro power plants
• Dispatchable renewable energy: pooling of micro-CHP units as balancing Virtual Power Plants, thanks to smart grids (Lichtblick, Bloom, etc)
• Demand-side management: contracted loads curtailments with commercial or residential customers, thanks to smart-grids (EnerNOC, Comverge, etc)
• Energy storage systems: use of energy storage to smooth renewable generation output and better serve the grid at peak (H2 storage but also flywheels, compressed air, flow batteries, etc)
Compared to other solutions, energy storage has the advantage of being versatile, however when it comes down to comparing costs, it has a clear disadvantage as it is still at early stage development. However, the increased need for flexibility, the limitations of pumped hydro, means there is room in the future for a competitive energy storage solution to emerge.
The energy storage market cannot be considered as a whole as it is specific to a region, an energetic and policy context, applications and needs. In order to understand the market potential for alkaline electrolysis coupled to renewables, therefore a segmentation market is proposed by region and application.
From the applications identified, ELYGRID should have more impact on the field of generation and economic optimization (direct link with renewables deployment). The first segment size at 2500MW in 2020 was identified equally split between Europe and USA, being the last one more difficult to access, in line with : NREL (USA) – The Value of Energy Storage for Grid Applications (May 2013), Imperial College (UK) – Strategic Assessment of the Role and Value of Energy Storage Systems in the UK Low Carbon Energy Future (June 2012)
Considering that hydrogen may be used as energy storage in several ways (to produce electricity, to produce liquid fuels and chemicals or to produce H2/CH4) the following conclusions about the potential impact on the market:
• Electricity-to-electricity solutions are not a path to pursue for alkaline electrolysis because it is an expensive solution with limited yield. Therefore, this option will need technology breakthroughs to be competitive with other flexible solutions. Some of the drawbacks are shown in the following:
o Intrinsically high technology costs (fuel cell membranes)
o Limited yield with 35-40% efficiency (raising energy price)
o Limited lifetime of the system
o Short response time, but no instantaneous
• PtL is only applicable at a large scale, with low energy costs and high value liquids
• PtG is also applicable at smaller scales, however the value of the gas generated is very challenging without subsidies. PtG is better thanks to its scalability and simplicity, but however there are still some drawbacks for PtL and PtG options:
o The liquids address to the fuel and chemical markets and are subject to their underlying commodity price volatility.
o Low value PtG gases. Unless self-consumed and access to gas grid is required.
o Low energy density of PtL output (DME 22 MJ/kg) [H2= 120, Gasoline=45, Diesel=34]
o Ptl and PtG rely on high cost electrolysers which would operate at part load, further challenging the economics
o Also, large scale flexible electrolyzers are not readily available
PtG can serve for several applications within 2 segments selected for alkaline electrolysis coupled to renewables.
The main conclusions of the market studies showed that several complementary action channels have to be activated to stimulate market emergence:
• Regulation
o Grid access: allow H2 injection to gas grid
o Blending targets: ensure dedicated share of “green” hydrogen into final products
o Subsidies: provide specific financial incentives for PtG (tax credits, FiT, depreciation)
• Technology
o Flexibility: focus research on alkaline electrolysis flexibility
o PEM size-up: focus research on PEM electrolysers size-up
o Hybridization: innovative with complementary hybrid systems: H2+flywheel, H2+ultracaps, etc
• Applications
o Market combination: with new technologies, explore new revenue combinations
o Tri-generation: explore H2-based tri-generation: power+heat+cold
o Micro H2 grids: transpose the smart building segment to microgrids&islands
To provide the long term impact at commercial level, one of the first steps is identifying the adequate stakeholders, enablers that have to be contacted when going to market strategy. Besides the public bodies and institutional sectors, there are other agents that are key to assure the commercial impact of this kind of solutions, like
• Grid operators
• Advisors: Research organizations/Energy markets
• Prospects: Utilities, IPPs, ESCo’s
As it has been stated before, the commercial plan for the overall Elygrid solution is expected to have a long-term development, especially taking into account the results and analysis regarding the market niches and the prospects from stakeholders for the technology.
Exploitation of the results
The project has a well oriented market approach with the clear leadership of the electrolyser manufacturer IHT. Having worked with an incremental and modular approach to the improvements has been useful to develop several designs that can be considered in pre-production phase. Since the very beginning of the project, the consortium has been oriented to merge the different developments of each partner in a potential advanced electrolyser at the end of the project.
By doing it, the results can be exploited in the easiest way by bilateral relationships between the electrolyser manufacturer and the partner in charge of the development. The further development or the decision of pursuing or continuing the line of work has to be decided individually by the partners or as joints developments, as it has been stated and granted by the Consortium Agreement on IPR issues. The assessment of potential commercial possibilities has been carried out during the project, and the potential impact at industrial level has to be pointed out for the developed solutions and the market prospective.
The following results obtained in the project could be included in a potential advanced electrolyser:
• Power electronics: Ingeteam has developed a power stack prototype that has passed the quality tests and has received the internal approval and readiness check-up for pre-manufacturing. On the other hand, the design made within the project renders the power stage apt for other market applications
• Membrane development: EMPA and VITO have been working on the development of new potential materials for using as membrane in an alkaline electrolyser. Both partners have identified potential industrial manufacturers interested on the market production of those materials at large scale
• Control system: Inycom, being participant on the control strategies definition, hardware installation and software development of the configuration, monitoring and control tool for the electrolyser, has established itself as a capable provider of technological solutions at industrial level, as far as this development can be used as part of their portfolio as showcase of the company’s R&D department abilities
• Mechanical equipments: Lapesa, as vessel separator manufacturer, has developed different units regarding the electrolyser as gas separators, head plates, tie rods and feet. These equipments have been designed according to the update pressure equipment directive
• Balance of plant design: FHA has designed a plug&play BOP for a mega watt alkaline electrolyser in a standard container. Besides, auxiliary units as water supply system and purification unit have been also designed in accordance with the operation conditions defined in the project.
To summarize, the project has been success on testing a new cell topology with 70% stack efficiency, design a new BOP electrolyser with a capacity of 2.98 t/d and with a global cost of much less than the FCH2-JU objective for 2020 of 2M€/(t/d).
Dissemination activities
From the beginning of the project, and in order to achieve also the expected impact on different public and communities, the dissemination activities were planned as key to reach the public and stakeholders. More specifically, the actions planned were the following:
• Development and maintenance of the website in order to reach to the technical community and the general public, to communicate the advances in the project and the results.
• Publication of the results in specialized magazines and scientific journals.
• Elaboration of a press kit.
• Presentation in specialized international and national conferences and events, such as the annual FCH-JU General Assembly.
• Guided visits to the testing facilities.
• Workshops or events, oriented to the participation of industrial and stakeholders interested on the technology, but also general public to show them about the benefices of renewable energy and hydrogen storage technologies.
The project has been presented to 21 conferences. FHA has been the main attendant to the conferences as project coordinator but it has been remarkable the efforts done by EMPA and JÜLICH to disseminate their results. The complete list of the conferences has been uploaded to this document.
The appearance in mass media has been framed to the launch of the press release at the beginning of the project by the FHA and an event attended by the FHA in June (2014). There has been another press release announced the end of the project, the main results and the final event together with the RESelyser project.
Regarding publications, the Elygrid project has been more oriented to provide solutions and technology to the electrolyser manufacturing sector rather than develop scientific material to public disseminations. It is important to remark that confidentiality matters have been taken into consideration when some public scientific communication has been proposed by a partner.
Most of the partners have been focused on including their developments in the potential MW electrolyser and for this reason it has been considered more appropriate to limit the communication in aspects such as membrane development (VITO, EMPA), cell topology (IHT), power electronics design (INGETEAM), control development (INYCOM) or new BOP design (FHA). The main publications are related to the modeling of the BOP and the Life Cycle Assessment. There has been just an article based on a LCA review published in a peer-review journal but other articles in LCA, modeling and safety risk analysis have been prepared and they are under revision nowadays.
The project has also been presented in events and workshops with stakeholders. The project was presented in the workshop organized by the FCH-JU/NOW called “Electrolysis day”, by an oral presentation done by FHA. At the end of the project, FHA has organized two different events to make diffusion of the results and a continuation plan of the project. A joint workshop was presented as a technical meeting together with RESelyser project in order to share public results and try to look for further collaboration between the different partners. The other event has been the presentation of the results to all the FHA stakeholders (more than 60 companies) in the general governing board. It is considered very important as some of these companies could have potential interest in the results obtained in the project as potential end-users of the technology. These companies are summarized below:
• Endesa -> Spanish utility (electricity and gas)
• Iberdrola Renewable -> Spanish utility (electricity and gas)
• RWE Innogy Aersa -> owner and promoter wind farms
• Wind Energy Promotion Association, Aragon Wind Energy Company, Aragon Wind Energy Association -> three different associations with interest in the further deployment of wind energy at local and national level
• Enhol Group -> owner and promoter wind farms
• Taim Weser -> promoter wind farms
• Gamesa Energy -> promoter wind farms
The website has been the other driver for communication and dissemination activity. It has been periodically updated with the presentations done by the different partners and with news related to the topic.
The website has been regularly visited. The total amount of visits has been 65.506 skipped between the different years. There have been more visits during the last two years of the project once the communication activities have been progressively increasing.
It is especially interesting to know the high ratio of visits from North America, showing the potential interests of this technology in the USA market. It could be related to the growing interest of methanation process in USA, where large amounts of hydrogen are needed to produce syngas. If this classification is done by countries, it can be seen as obviously the main contributor to North American visits is USA and Germany, Russia, UK, France and Spain in Europe.
As final remark of the dissemination activities, it can be concluded that they have been fruitful reaching to different publics through the adequate media, and it has been possible to make contact with stakeholders and technological agents implied in the energy, renewable energy and hydrogen sectors. As drawback, the commercial or industrial orientation of the project has caused that the scientific production has been limited, mainly due to IPR issues.
List of Websites:
Project website:
www.elygrid.com
Coordinator contact details:
Fundación para el Desarrollo de las Nuevas Tecnologías del Hidrógeno en Aragón
Ctra. Zaragoza, N330A, km 566, 22197. Cuarte (Huesca)
info@hidrogenoaragon.org
The project has achieved significant results in all the fields. A new cell topology has been developed with better efficiency and working at higher current densities. By using this, more hydrogen per unit can be produced, decreasing the total cost of the hydrogen produced. As well as this, the new cell topology shows better values of efficiency and therefore will improve the value of operation costs.
To increase electrical efficiency, new power electronics have been designed, based on IGBTs with the capability of working properly and with good efficiency coupled to renewable energy sources. This will improve efficiency during operation and therefore decrease the operation costs.
A new BOP has been designed which includes all the components of a MW electrolyser in the same container. It will decrease costs during the erection and commissioning of the electrolyser and will therefore provide a more competitive unit. A new control system has also been validated in order to work properly alongside renewable energy.
Field-testing has been carried out with successful results. The main goal has been to test the standard market sized electrolyser (1600 mm of membrane diameter) in order to pave the way for future commercialisation. The electrolyser has been working properly at double current density showing good values of V/cell and gas purities.
Much work has been carried out in order to aid market preparation and dissemination. The Regulation Code and Standards (RCS) to put an electrolyser in the market have been analysed. A cost assessment has been done, showing an overall cost reduction of 30% in comparison with the technology at the beginning of the project. A life cycle assessment (LCA) has also been done, showing that the new technology is less harmful in terms of environmental performance.
To summarize, the project has been success on testing a new cell topology with 70% stack efficiency, design a new BOP electrolyser with a capacity of 2.98 t/d and with a global cost of much less than the FCH2-JU objective for 2020 of 2M€/(t/d).
As regards the exploitation of the results, the project has a well oriented market approach with the leadership of IHT. These big units producing hydrogen at high pressure (33 bar) could be used to produce large amounts of hydrogen for power-to-gas applications, helping the hydrogen fuel cell vehicles deployment or for classical industrial applications. Therefore, they can have a direct application and market once the project has finished.
Finally, the different improvements achieved during the project (cell topology, power electronics, BOP, control system) could be directly integrated in the IHT technology, increasing their competitiveness and broadening their potential possibilities in the different short-term hydrogen markets. In this regard, the project has been working on building strong business alliances between partners which will make easier the future technology exploitation.
Project Context and Objectives:
Context and previous analysis
An inherent feature of renewable resources is that electricity generation cannot be fully forecasted and does not usually coincide with the demand curve. As penetration of renewable energies increases, current grid code requirements become stricter and not only they find deviations from predictions but also they are more demanding of the reactive behaviour of wind farms. Hence, a way to store energy is foreseen to be needed when the percentage of renewable electricity share is high in order to help managing the grid. Enabling a certain storage capacity within the wind farms would help to reducing the gap between the generation and the demand curve, as well as damping abrupt variations of the wind power generation. There are various possibilities for the storage of electricity such as pumping by means of hydro power plants, batteries, compressed air energy storage (CAES), flywheels, and hydrogen. Among these, pumping is the most frequently used. And also although less frequently, the energy is also commonly stored in batteries, but their size requirement is a costly drawback. Under these circumstances, hydrogen constitutes a competitive storage technology, either for round-trip electricity production, for co-production of hydrogen as an alternative fuel or to be injected to gas grids. This option relies completely on a robust and cost efficient electrolyser technology of MW scale.
There are mainly two electrolyser technologies available today: polymeric and alkaline. Polymeric electrolysers, although quite efficient, are limited to power stack of the order of kWs to hundreds of kWs, whereas alkaline electrolysers stack range between a few kilowatts to several megawatts. Wind farms are in the last range (typically 20-50 MW), and nowadays, there are only a few electrolyser manufacturers with the know-how and the capability of manufacturing such high capacity electrolysis units. On the other hand, electrolysis units that are able to operate at high pressure show many advantages over atmospheric ones, such as savings in the compression unit downstream of the electrolyser and faster reactive capacity of the stack and enabling longer standby times (required for intermittent operation and low capacity factor).
Although the theoretical efficiency of electrolysers can never be reached because the process deviates from idealness due to thermodynamic losses as well as material limitations, the current electrolyser efficiencies generally range between 52% to 70% (HHV) for both alkaline and polymeric electrolyser, leaving a big potential for improvement. Another important point to be analysed and studied is that nowadays there is no available technology developed for partial load or intermittent operations within that range of electrolysis power. New developments are necessary to match renewable electricity production with its intermittent nature. Current technologies must be redesigned to achieve higher efficiencies and to be reliable, robust and competitive with capacity factors lower than 25%.
Objectives and the Elygrid Consortium
Taking into account the previously described scenario and potential market niches, ELYGRID Project aimed at contributing to the reduction of the total cost of hydrogen produced via electrolysis coupled to renewable energy sources, namely wind turbines, and focusing on megawatt size electrolysers (from 0,5 MW and up). Work has been aimed to the improvement of the efficiency and the reduction of total cost of ownership, through design tasks, modelling and development works and demonstrative tests of the technology in a market diameter scale facility. The baseline used as reference within the Elygrid project corresponds to the state of art alkaline electrolyser from IHT, partner in the project, being a manufacturer that nowadays has installed worldwide and running MW capacity alkaline electrolysers for hydrogen production.
Basically, a MWAE is composed of 3 subsystems: cell stack, power electronics and balance of plant (BOP). Current designs are suited for more than 97% factor capacity and to run most of the time at full load . To match the intermittent nature of renewable energy sources, and specifically wind energy, a re-design must be made. The re design and test efforts oriented to obtain incremental improvements on the design were focused on these three different areas. To achieve the global goal stated before, the focus on the three different sections of the electrolyser system has facilitated being able to target a broad list of objectives, previously defined on the Elygrid Description of Work, which is summarised below:
O.1 Definition of new operation conditions of the electrolyser for improvements in performance and efficiency.
O.2 Increase the current density by a factor of two (relative to baseline electrolyser), maintaining the same diameter stack, hence doubling the nominal production of the SoA electrolyser.
O.3 Development and study of new diaphragm/membrane materials, attaining controlled porosity, sufficient mechanical strength and low cost, capable for elevated operation temperature and increased electrolyte concentration.
O.4 Improvement of stack materials and components in order to increase electrolyser efficiency (by reducing cell voltage), reliability and durability, supported by advanced modelling.
O.5 Identification of the limiting factors for the membrane functionality (like aging, contamination, etc...) by means of micro-structural analysis (SEM, TEM, EPMA).
O.6 Reduce the cell voltage (current 1.9 V/cell to 1.6 V/cell target) by raising the operating temperature up to 100 °C and reducing the resistance of the cell assembly (membrane, electrodes, and electrolyte). The objective is to achieve an increase of the stack efficiency by +10%.
O.7 Specify process and instrumentation diagrams -P&I D- of a 6 MW electrolyser.
O.8 Identify technical improvements related to the Balance of Plant (BOP) which represents approximately 16% total alkaline electrolyser capital cost (cost reduction estimated: 5% of the total capital cost).
O.9 Re-design power electronics, less sensible to the electrical grid parameters, and study and optimize power electronics considering factors like efficiency, harmonics and reliability (electricity energy consumption reduction 10%).
O.10 Design, develop and test the concept of converters for 3.300 A DC and 800 V.
O.11 Field test of new stack built according to the membrane and stack developments.
O.12 Identification of technological market and local value-chain suppliers.
O.13 Assess total investment reduction cost of 25% (BOP cost reduction 5%, stack cost reduction 20%).
O.14 Outreach, social awareness and promotion of alkaline electrolysis coupled with renewable energy sources through demonstration projects, field testing and integration.
O.15 Shed light on RCS aspects for electrolyser technology to facilitate commercialization worldwide.
O.16 Comparative Life Cycle Assessment (LCA) studies carried out according to the practice guidance developed by the FCH JU.
This objectives’ list was already pointed out in the DoW taking into account the capabilities of the consortium behind ELYGRID project, which consists of a complementary team of academic, research and industrial partners with know-how in renewable energies, electrolysis, membrane separators design and characterization and energy demand management, from which several synergies have been possible, helping to the fulfilment of the project objectives through the tasks defined to reach them.
Fundación para el desarrollo de las nuevas tecnologías del Hidrógeno en Aragón (Foundation for Hydrogen in Aragón or FHA [Spain]) has carried out, among other tasks, the coordination of the Elygrid project. FHA is a private non-for-profit research centre promoted by the regional government and more than 60 public and private stakeholders. FHA has also been a key partner for the BOP development and design tasks, together with the field tests carried out at full scale electrolyser’s diameter, thanks to the already installed scalable electrolyser (1.6 m diameter, operation pressure >30 barg) which has been available for stack testing within the project.
Industrie Haute Technologie (IHT [Switzerland]) is a company with more than 40 years of experience in the electrolysers’ manufacturing field. Its role in the consortium has been related with stack design, manufacturing and testing (at pilot scale and full diameter stack) and with assessment and monitoring of costs for the new developments together with market preparation.
In order to join efforts at European level and in tasks related to membrane development, two entities (VITO [Belgium] and EMPA [Switzerland]) have been focused on designing, testing and characterizing new membrane separators materials for the electrolysis cell.
EMPA, Swiss Federal Laboratories for Materials Science and Technology, is a fully independent public research institution with 800 employees. The Laboratory “Hydrogen & Energy” has been involved in development and study of new diaphragm/membrane materials, as well as in the identification of the limiting factors for the membrane functionality like aging, contamination etc. by means of micro-structural analysis techniques.
VITO (Flemish Institute for Technological Research) implements client-driven research projects and develops innovative products and processes. Around 15 years ago VITO developed the ZIRFON® composite separator, which showed very high potential for solving the drawbacks of other alternatives to traditional membranes, but its use is limited to certain applications, due to the limited mechanical properties. VITO has been working on developing better separators based on ZIRFON® along on characterization of them.
Instrumentación y Componentes (INYCOM [Spain]) was created in 1982 with the aim of delivering services and solutions on IT, analytical technology, electronics and electromedicine. Nowadays, besides keeping its original orientation, a consolidated R&D group in the company has acquired valuable experience in the fields of instrumentation and control of industrial systems, along with the development of products in distributed power systems and smart grid solutions. INYCOM has provided the consortium the know-how on controlling and monitoring the electrolyser, while developing an improved control system for field testing.
Ingeteam (INGETEAM [Spain]) has worked on the specifications, design and testing of new power electronics systems which could integrate grid and electrolyser in a more efficient manner. Ingeteam provides application engineering, including turnkey projects on electrical equipment. Along the years, the company has also specialized on design and building electrical equipment, executing high and low voltage installations, with scales ranging from kW to megawatt, in power generation plants or in marine and railway traction applications, among others.
LAPESA [Spain] is the head of a group of companies, experts on manufacturing and marketing products focused on pressure tanks and pressure equipment. The R&D group, located in Zaragoza, has worked on the mechanical redesign of main parts of the electrolyser, in order to update the materials’ usage aiming at lowering the costs. Besides, the experience of LAPESA has been very valuable in the development of the RCS studies that were developed in the project.
The sections IEK 3 and IEK STE of the Institute of Energy and Climate Research with in total about 150 employees are part of the Forschungszentrum Jülich. (FZJ [Germany]). The experience on static simulation of alkaline electrolysis, stack simulation, life cycle assessment of new technologies and energy systems modeling have been a key part of FZJ commitment in the development of dynamic models of the electrolyser integrated with RE along with the LCA studies carried out.
As far as market studies and possibilities for new markets’ strategies, Areva Stockage d’Energie (AREVA [France]) has provided to the consortium its experience on sustainable energy solutions assessment, energy management and fuel cell and electrolyser systems development and market segmentation.
CEA-LITEN (CEA [France]) is the Laboratory of Innovations for New Energies Technologies from CEA, French Governmental Research Organization devoted to both fundamental and industrial R&D in the field of energy, information and health technologies and defense. It addresses several renewable energy applications including hydrogen production, storage and fuel cells (SOFC and PEFC). Having already a good experience in electrolysis techno economical evaluation and in testing and modeling high temperature electrolysis and PEM electrolysis cell and stacks, CEA-Liten has been involved in modeling at cell level, and in developing a techno-economic analysis.
Project Results:
1. Power Electronics
Aligned with the objectives of redesigning the power electronics to assure an efficient connection between electrolyser and renewable energy grids, Ingeteam developed the tasks required to design the power electronics module, develop a concept converter and testing it as a concept prove previous to commercialization. As grid and load specifications had to be defined in the first steps of the project, the strategy followed required:
• Set of specifications regarding the integration of the baseline electrolyser with RE energies
• Development/construction/testing of a power module as defined
• Conceptual design of the power module for the electrolyser working at double current density than the baseline
Starting with the proper characterization from an electrical point of view of an alkaline electrolyser and according to the empirical data measured with the base-line system available at the FHA premises, Ingeteam created a complete electrical behavioural model to simulate the load to be fed by the converter, considering its dynamics, restrictions, operational range and the rest of the specifications of the electrolyser.
On other hand, from the wide analysis of possible topologies to use as interface between the grid and the electrolyser defined in previous stages of the investigation, only three of those were analysed here in depth.
• The first design proposed is formed by a classical converter and has been oriented to an industrial scenario where grid conditions are supposed to be stable and special connection specifications (flicker and LVRT) neglected.
• The two new remaining designs based on IGBTs have been designed for a more restrictive scenario generally related to renewable energies integration where particular grid conditions and restrictions have been considered for the design process.
Simulation results show that the first topology presents the best efficiency but has some drawbacks as its power quality and grid stability dependency. The two other topologies present a slightly worse efficiency compared to the previous one but both offer better power quality and response to grid instabilities.
The second converter design was selected as the one with the best balance between electrical features and cost, number of elements, simplicity and volume, so this topology shall be considered as the starting point for the future development of a prototype.
Once the adequate power electronic topology oriented to the hydrogen production via alkaline electrolysers has been selected, and its design validated through simulation, the commissioning of the converter prototype was carried out.
A test bench to validate the prototype was also commissioned which was constructed so that it might test two power stacks set in parallel. The power module design was tested using the standard battery of tests and checklists for other products of Ingeteam (including temperature rise, insulation, cooling circuit, power stack elements,…). The results have met all quality standards and accordingly the design and prototype has received the internal approval and readiness check-up for pre-manufacturing.
Once the power module was accepted as valid, an advanced power conversion unit for advanced electrolysers was designed. A new conceptual power conversion stage adequate to feed the latest generation of the advanced alkaline electrolyser was considered. The electrolysis stack marked as objective has to be able to work with the current densities in the range of the FCH-JU objectives maintaining the same number of cells.
The modular design, on which the selected power stack design is based, makes it possible to design a “Custom-Made Configuration” for each case and application. One of the main advantages of the selected and built power stack was its modularity in terms of power. Besides, this new design achieves efficiency improvements round 10% taking into account the operation profile of the electrolyser. This asset represents several advantages not only for the developers and suppliers of the solution, that is to say, Ingeteam, but also for the purpose of this project. On the one hand, the fact that the design is modular enables an obtainable and to a certain extent “easy” solution to account for any, present and near-future, further material and mechanical advances of said Electrolysers. And on the other hand, it renders the power stage apt for other market applications such as the wind power sector.
It should be carefully analysed how many power stacks in parallel should be used to handle the specified values of current. The scalability of the power stack solution could be obtained through the parallel connection of multiple power modules. Parallel connected power modules offer power scalability advantages but request outstanding precision at the time of synchronizing the current and voltage measurements.
Ingeteam has an extensive experience and expertise in the field of power converters in which parallel connected power modules are used. The synchronization between the converter control unit and the power modules can thus be considered as a proven solution within Ingeteam products.
2. Membrane development and tests
Membrane development within Elygrid project was mainly carried out by VITO and EMPA. Two different approaches can be described.
First, a novel one-to-one replacement for the baseline previous technology used in the MW electrolysers by IHT, which additionally leads to improved cell efficiency, had to be developed. In the first design considered for the Elygrid project, new membranes topologies were compressed to fit the distance between the electrodes. The first new concept to be developed had to be designed and tested to fit in the same cell gap.
On the other hand, a lower ionic resistance membrane, in the range of the comparatively commercial membranes was highly desirable for reaching the goal of higher cell efficiency.
The development of thinner membranes has to be related with changes in the original baseline cell configuration, in order to assure a proper fitting and contact between membrane separators, electrodes and bipolar plates. The use of thinner membranes aimed also at achieving lower resistances and better cell efficiency.
For each one of the paths described above, several samples were developed, being compared and described after characterization battery tests documented from the beginning of the project (ionic resistance, pore size, permeability, corrosion resistance, bubble point measurements). The most promising ones after this screening step were tested at lab scale and then the selection continued to pilot scale at the real operating conditions, in small diameter electrolysers, before selecting which one was better suited to be built at full size and installed (1600 mm diameter) for the field experiments. Cell voltage and efficiency was also compared to reference cases (previous membrane and commercial membranes).
Path 1: Composite and multilayer membrane separators (EMPA)
The choice of materials for separator production was based mainly on chemical stability, due to the severe desired operating conditions (when electrolyte conductivity is near its maximum). Synthetic and natural materials were investigated as fillers while polymer materials felts and fabrics were decided to be used as support to provide the necessary thickness.
Corrosion experiments were carried out to provide input about the compatibility of the materials in a KOH medium, after 8000 hours in 25% KOH(aq) at 85°C. The results showed a significant dissolution of mineral materials, including the reference, while synthetic materials showed lower corrosion rates.
Investigations on the influence of different filler types, PSF concentrations and filler to binder ratios on the final separator material were carried out. The resistance of each separator has been measured in U/I curves and compared to commercial separators from IHT. The reference materials abbreviated as A1, A2, A3 and A4 have shown the differences in ionic resistance, as possible to see from U/I characteristics in, in relation to their porosities. The lowest ionic resistance has been achieved for sample A4.
Path 1: Dual layer concept membrane separators (VITO)
VITO proposed a dual-layer concept in which the first layer act as a distance holder to fill up the open space, whereas the coated separator layer needs to fulfil all tasks expected from a separator (high BP, low resistance,). First, all the candidates support materials were characterized for their ionic resistance, resulting in a better behaviour for the spacer fabrics due to their open structure.
In a second stage, VITO developed different configurations of supports and coatings by changing the thickness of the final solution and assessing the main physico-chemical properties. It was significant the efforts carried out to find the best support material with a good performance in order to work in the operation conditions at 30% KOH, 80ºC and 30 bar. Besides, all the permeabilities and bubble point of all the membranes were compliant and compared with those taken as reference.
Path 2: Asymmetric membranes (EMPA)
On the basis of experiments, thermodynamic modelling and membrane leaching experiments, Mat 2 and Mat 3 were selected as the materials of choice to continue developing improved membranes. Mat 2 due to its price and patent-free restrictions became a more attractive alternative, besides its low resistivity and low permeability to gases.
The membranes developed can be categorized in three different classes, depending on the microstructure modification technique. The thinner membranes developed within “Path 2” were compared in their characterization and behaviour against a reference commercial membrane and as the reference behaviour of previous technology membranes.
The resistivity of the new developed membranes was in any case lower than the commercial reference material and a bubble point pressure characteristic of each of the methods used, which will be used as selection method to be tested in the electrolysis lab scale cell.
Path 2: Symmetric membranes (VITO)
New membranes were developed by VITO via phase inversion process. The separators represents more symmetrical concept by means of surface similarity, not being its entire microstructure identical. The developed membranes were produced aiming at having three different classes or variants, taking into account different combinations of permeability, bubble point and pore size distribution.
Especially resistivity has been drastically improved when compared to commercial reference membrane (and of course compared with previous technology reference membrane). Simultaneously bp pressure show better (or much better) chacacteristics.
Thin membranes were tested in an electrolysis setup at high temperature and pressure, based on the preselection criteria. The list of specimens was narrowed down to membranes representing the extreme parameters (two by VITO and three by EMPA) having different combinations of bubble point, resistivity and permeability in order to assess the effects of these characteristics in the gas purities and the voltage. Additionally, the commercial reference material was tested under the same experimental conditions.
From this comparison it is clear that all newly developed membranes have performed better that SoA separator which had been previously used by IHT. The lowest voltage drops have been obtained for B44 and V27 membranes, which have almost identical I-V characteristics. The calculation of the gas production increase for the same voltage between commercial membranes and B44/V27 results in a 13% yield.
The in-situ measurements however do not exactly represent the trend reported from the ex-situ zero-bias resistivity measurements, carried out during the preselection stage. Since at higher current densities, the concentration overpotential dominate and because used electrodes as well as the cell assembly are identical, it can be hypothesized that the reason of the results discrepancy is related to either:
• Dynamic conditions during the electrolysis: the interface between the electrode and the membrane indicating different hydrophobic/hydrophilic properties, which are not taken into account during the ex-situ static measurements
• measurement error of the zero-bias resistivity, which is more sensitive to specimens of a smaller scale
• an overlap of both effects
Electrochemical tests of selected separators
During the project mainly three electrolysis test setups have been employed. The main differences, beside the operating pressure and temperature, are the electrodes, which were installed into the electrolysis cell. Their short description could be summarised as follows:
• Ambient temperature/pressure electrolysis cell with an acronym: Electra 2. This setup has been constructed within ELYGRID projects and established the basic results for the modelling. This setup was equipped with electrodes supplied by IHT. The diameter of the electrodes amounted to 46 mm.
• High pressure high temperature electrolyser working in the stack configuration with an acronym: Voltiana. This setup was purchased from H2 Nitidor (Italy) and used during the last stage of the project. The electrodes incorporated into the Voltiana stack are sand-blasted Ni meshes, having 113 mm diameter. The electrochemical tests were based on a 7-cell stack configuration.
• Ambient temperature/pressure electrolysis cell with an acronym: Electra 3. Electra 3 has been constructed during the last year of the project as an improvement of the Electra 2 design. The cell employs 2 hot wire-cut coarse Ni electrodes with a diameter of 25 mm.
3. Balance of plant optimization
The goals of the project related to BOP was related to identification of improvements that could derive in a cost reduction of the 5% of the CAPEX. The tasks on BOP optimization have also taken into account the OPEX, in order to find a compromise in the final TCO.
Capital cost reduction was studied as objective through
• Mechanical re design (reduce the use of materials)
• BOM review
• Commissioning costs
Aligned with the European scope of the project, the selected code for the redesign of the main mechanical components of the BOP was EN 13445, which is the European code for the construction of unfired pressure equipment and it is harmonized with the Pressure Equipment Directive (97/23/EC). A review of the code design was of key importance in order to systematize the design process of the equipment to develop, including materials quality definition, safety factors, test groups and coefficients. LAPESA, applying the aforementioned design code, proceed to develop the review of the classic design of head-plates, tie rods and supporting feet of stack and gas separators. The mechanical redesign of gas separator and mechanical parts of the electrolyser was done for 37 bar, 120°C and 1.6m (cell’s diameter).
The design of heads, bolts and studs and head-plates showed to be only dependant on cell diameter and pressure, not length (meaning that the final number of cells, which provides a stack length influences only the number of supports)
The mechanical redesign done to gas separators, head plates, tie rods and feet have showed a significant opportunity to reduce costs and the manufacturing process has been updated following the standard used nowadays. This new mechanical design, developed in accordance with the standard EN13445 shows that an improvement of the cost reduction in the gas separators of 10% (30% decrease in weight) and in the other components of 5% (10% decrease in weight) could be achieved.
In accordance with the cost breakdown for the reference unit (3,5 MW) provided by IHT, a 14% of CAPEX is due to on-site works during the erection and commissioning of the electrolyser. It means that this cost is as significant as the Power electronics or total BOP costs. Therefore, it can be concluded that, at least for units as the reference one, the reduction of the commissioning costs is a key issue to be addressed.
In order to reduce the on-site works, a modular design of the system is proposed. Several tasks are being developed to achieve a modular design:
• IPR and market analysis
• Container definition
• Equipment distribution inside the container
• RCS assessment
• Equipment design and specifications
• P&ID and Bill of Material
• Risk analysis (related to P&I D and control strategies definition)
• 3D Design
After assessing the adequacy of pursuing a modular and containerized design, before starting with the bill of materials review and redesigning the process and instrumentation needed, other studies were carried out regarding the container definition. FHa developed a calculation tool with which preliminary weight and equipment calculations were done to fit the whole electrolyser system in a standard container. Continuing the results from the sizing tool and the transport cost study, an analysis of distribution possibilities was done, revealing that the assembly operations could be also divided into two principal tasks: stack assembly and BOP assembly. Indeed, this differentiation would also allow executing the main assembly tasks in parallel, obtaining also a better work flow distribution in the workshop.
Once the stack power and expected behaviour (determined also according to the test field results of the possible new membranes) the rest of the BOP components were also specified according to a P&I diagram. This P&I was the subject of several reviews, mainly related to the safety and risk analysis that was being carried out for each version.
A complete bill of materials was addressed finally, including operating range, materials, models and price for each component, in order to assess a complete design which could be considered as pre-production for a new concept electrolyser system. The complete BOM included components which can be categorized as:
• Pressure equipment (gas liquid separators, heat exchangers, filters, etc)
• Valves (control valves and electro-pneumatic actuators, check valves, pressure relief and safety valves, drains and purges and bypasses operations)
• Field instrumentation (manometers, flowmeters, level transmitters and gas analysers, both normal control instrumentation and safety instrumentation)
• Pumps
Besides the standard BOP, two other auxiliary systems were designed and specified: the demineralised water production module and an external purifying module to decrease the oxygen and water content to use the hydrogen in a fuel cell.
Comparisons of the overall system cost breakdown with the state of art alkaline MW electrolyser is described with detail in the next section, but as a basic comparison to state the fact that the objective of lessening the commissioning and initial costs is being achieved, the gross BOP cost reduction has been of around a 20% when comparing the same basis (e.g. including - or not - peripherals systems, i.e. water production and hydrogen purifier), while if the comparison is made taking into account the hydrogen production (cost per Nm3/h of H2 produced), the cost of the BOP for the Elygrid container design would be half the state of art BOP cost. It is important to mention that, in spite of the containerized nature of the new design, packaging costs are expected to be not much higher than those of the state of art BOP.
Due to onsite commisioning personnel costs, transportation and logistics costs involved in the erection of an electrolysis plant, several improvements were studied in order to design a compact plant. This new design involves the following advantages:
• Transport costs reduction. BOP container is now standard size
• More space within the container, facilitating maintenance
• Greater flexibility to increase the electrolyser power
• Lower reparation cost in case of an equipment failure
The auxiliary modules (water deionization and hydrogen purification) are designed in 10’ containers. These modules could be (optional) installed next to the stack and the BOP container. Hydrogen purification module is a flexible module, it can purify up to 2200 Nm3/hf hydrogen. It’s situated downstream the BOP container. It needs N2, water and power supplies. Water demineralisation unit produces 2000 l/h of water with conductivity less than 1µS/cm.
The BOP module is fitted in a 40’ container. Priority has been given to the assembly and maintenance operations. It has been designed in order to facilitate the work inside the container. Also the worker would have access from different points, letting do the maintenance in pairs, according to the ISO 15916 standards.
The main (bigger) components of the BOP were distributed in order to keep balanced the mass centre of the container. The free space was conceived to be used for control valves panel and the gas analysis cabinet. In order to facilitate the main assembly operations, valve panels are pre-assembled before being mounted in their final position inside the container.
A free space has been created to let the workers get in and calibrate gas analysers, replace gas bottles, calibrate flow sensor, etc. All the process conections with other modules are in the back-side of the main container. These flanges are welded to the back wall in order to increase the mechanical resistance of the structure.
As final conclusions, these two achievements should be pointed out:
• New BOM for the optimized BOP: the complete BOM has been reviewed, starting with the baseline, redesigning the processes and process lines, in order to seek a cost reduction while keeping or reaching better functionality and safety characteristics. The BOM has been also updated in term of costs, dimensions and specification sheets. The new system has been also extensively analysed from the safety point of view, being the subject of a qualitative and a semi-quantitative risk assessment studies, being designed under the pertinent RCS and being under an ATEX analysis. On the other hand, and together with the updated control system, a complete operation and maintenance manual has been developed for the new design. The cost reduction has been decreased dramatically as explained in the document.
• Modularity: allows decreasing costs executing most of the assembly operations at the manufacturer workshop, reducing the onsite works at the client facilities. Easing the maintenance operations has been also a key factor to take into account in the modular design. Not only the standard BOP (compared to SoA) elements have been designed and completed in a 3Dview, but also some peripherals modules, like demineralized water production and hydrogen purification unit.
4. Improved control system
The main goal was to define a new control system with improved functionalities and stable enough to be remotely operated coupled to RE. In the first steps, Inycom made a deep analysis of the original control functionality and performance identifying those areas which needed to be improved to reduce OPEX and increase the automation level of the process. During the development of the new control, the join work of Inycom and FHA has been a cornerstone to define a new control strategy, implement new operating states, establish the transition conditions between states and define new alarms and warnings.
All the operation states and their transitions were redefined in collaboration with FHA trying to automate to the maximum each process, aiming to reduce dead times and the need of human interaction. It was detected that there were several actions that requested the operator’s approval or even in some cases, the operator had to control part of the process manually. In the new control system all those tasks and most of the transitions between states have been automated completely, reducing the time needed to reach the production conditions as well as the time to stop and improving the work of the operators. Additionally, two new operation states have been implemented which increase the functionality and will help to reduce considerably OPEX and transition times.
In this part of the process, the prediction and forecasting models developed by Inycom play an important role. These algorithms are able to estimate the electricity cost 24 h before and the renewable energy production in the same time frame. This allows the system to choose between selling the renewable energy or to start the electrolyser for energy storage. For example, if it is expected that a high electricity price will appear in short time it doesn’t make sense to produce hydrogen therefore, the system will be stopped and when profitable conditions are met, the system will start again producing at full or partial load, depending on the predictions, without having to restart the system from the beginning with the resulting OPEX and time reduction.
The integration of renewable energy resources with the control could allow a better exploitation of the renewable energy produced since depending on the energy demand it can be chosen whether to store energy (if there is overproduction) or to sell that energy to the grid in order to assure the power supply.
Other control improvement has been related to the review of the control loops. After analysing the control of the plant, it was noticed that there were several PID controllers which were not well designed and tuned, and thus they were making the system become inefficient and in some cases not completely stable. This type of control could not predict the disturbances on the system and the PID controller only took into account the difference between the reference and the measured output.
The new control system, a feedforward control combined with feedback, has been implemented. With the feedforward control, the disturbances and changes of the system are accounted before they have time to affect the system. This fact can be especially beneficial for slow systems in which it takes a long time to observe changes in the measurement. Therefore, the feedforward control is used to give predictive information to the PIDs. The value for the feedforward is calculated by designing operation models which consider the value in real-time of the associated process variables and actuators. Feedforward models have been developed for the main components to control, resulting on a control system that copes much better with the process disturbances that can affect the stability of the system.
Finally, it has to be pointed out that the control improvements not only have been designed but also developed and tested with the 1600 mm electrolyser at FHA premises. A tailored web interface has been developed to monitor and control the process remotely. It has been done taken into account the operators’ needs, so that they can access easily to all the information they need. It can be accessed from any browser and from any device. This fact would help to OPEX reduction as the use could have people on call instead of present on location, which is cheaper. It will also reduce OPEX costs as one person will be able to be on call for multiple systems on multiple locations, instead of having one person monitoring each installation.
To sum up, the following tasks have been carried out in order to develop an enhanced and efficient control system of the electrolyser:
• Development along with FHA of a new control strategy for an alkaline electrolyser, including new operation states, warnings, alarms and operating modes coupled to RES.
• Selection and installation of hardware for the experimental plant. The installed hardware was chosen due to the high performance of its CPU, the availability of standard programming languages and the possibility of adding more I/O modules for a future expansion.
• On-site implementation of the control system ending up with a totally working product to control the alkaline electrolyser.
• Design of a control system (hardware and algorithms) scalable to MW electrolysis, tuning of the control system in the experimental plant at FHA facilities.
• Development of an intuitive user interface to monitor and configure the process on site or remotely.
• The design of the control system has been made keeping in mind the objective of decreasing OPEX by adding the possibility of controlling the system remotely, developing new alarms and designing new PIDs with feed forward control in order to obtain a much more stable and safe system.
5 System modelling and simulation integrated with RE
The rapidly increasing renewable wind and solar power capacities in European countries form the major background of current electrolyser development. This leads to increased shares of electricity that cannot be used in local distribution grids. In order to provide an economic utilization alternative for such electricity quantities hydrogen can be produced via water electrolysis and serve as a storage medium for renewable energy. The specific advantage is, however, its flexibility with respect to utilization, as it can serve as fuel for transportation, as feedstock for chemical industry and also for reconversion to electricity. The technical and economic viability of such energy pathways must be assessed.
Of particular relevance is the derivation of load profiles that result from the computational comparison of grid load and renewable power feed-in:
Pres = Pgrid - Pre
Pres is the residual power which is positive, if power from conventional generation is required for covering the demand. It is negative during periods of wind power exceeding grid load. Pre is the renewable power and Pgrid the grid load.
Such analyses must be performed on a regional if not local basis as the potential and intermittency of renewable power feed-in as well as the potential for renewable power generation installations are strongly dependent on their location. In this work the analysis is carried out for a location in Germany. As part of an ongoing PhD thesis at IEK-3 and outside of the Elygrid project, a regionalized model is being developed that allows the determination of time-dependent profiles of grid load and renewable power feed-in on a municipality (city) level. The clear focus here is at present on wind power which bears the largest potential for renewable energy production in Germany. For the purpose of the project a suitable data set had to be identified.
The requirements where set as follows: in order to ensure high annual load hours the local grid to be selected should provide:
• low grid load
• high potential for renewable power capacity.
• options of nearby hydrogen storage preferably in salt caverns
In accordance with these requirements the municipality of Friedeburg was selected. As it is in a rural region in the North-Western Part of the country it is characterized by low grid load and due to high (average) wind speeds – a high wind power potential. Moreover, salt dome formations are in the vicinity. Among different scenarios that are available for the regionalized IEK 3 model the “40 GW scenario” has been selected assuming a total wind power capacity of 40 GW for Germany. Even though this value is comparable to the actual value for Germany at present it differs from the actual situation as the location of wind power plants follows a cost-optimizing procedure in the model. In contrast, current installations can widely be found in regions with lower wind power potentials, due to the feed-in tariff regulations. The data selected for use in the Elygrid project are thus scenario-related and do not refer to wind power capacity distribution in Germany at present.
For the scenario calculations the negative residual power is being used and now defined as the surplus power Psur
Psur = -Pres -> Pres<0
Psur = 0 -> Pres>=0
Related to the utilization of the surplus power it is clear that 10 MW electrolyser considered here is not able to take-up all the power that is available. Remaining quantities can be provided to the transmission grid or have to be curtailed. This simplified concept of utilizing surplus power has originally been used in the German HYPOS project. In the literature a variety of other operational strategies for electrolysis is available, e.g. on the basis of time-dependent electricity prices. It is assumed here that 50% of the maximum surplus power is transferred to the transmission grid – this parameter is here defined as the lower operational limit of the electrolyser. This option is preferred over other alternatives as the greenhouse gas reduction effect is greater when conventional power production is substituted. Electric power that exceeds the 50% share is available for electrolysis. If also maximum electrolysis power is covered electric power must be curtailed or used otherwise, e.g. for power to heat applications. For visualization, an installed electrolysis power of 30 MW has been assumed. However, the scenario calculations refer to a nominal electrolysis power of the designed range [up to 10 MW]. The lower limit of electrolysis power related to the maximum surplus power is varied for the simulations.
The results shown that hydrogen production quantity, operating hours of hydrogen production and total electric energy uptake are decreasing when the lower operation limit is shifted to higher values. The system efficiency is stable at values ranging from 64 to 65%.
It can be concluded that the setting of the lower operational limit greatly effects the hydrogen yield from renewable surplus power. However, this factor can only be taken into consideration when installed wind power capacity significantly exceeds the grid load. This was given in the example of the Friedeburg municipality that was chosen in the present analysis.
6 Field tests (1600 mm diameter stack)
Field tests are referred to the studies and works done under the Elygrid project for the replacement of the 1600 mm cell stacks erected and commissioned by FHA and IHT. After the erection and commissioning of the first unit on site, tests were carried out to check the behaviour of the new membrane and its working point conditions, comparing with the traditional based membrane.
A first battery of tests was programmed with the new cell blocks. These tests were oriented to obtain a bench of results to compare the operation capabilities of the new cell block with the Elygrid base case.
The new cell topologies tested have increased an 8% the efficiency of the stack at the same current density of the previous technology. The gas purities of the unit are inside the safety range and enable to use the hydrogen in a fuel cell. The results were consistent with the values observed in the small diameter test bench (IHT) for the same current densities.
Several tests were carried out increasing current density, especially to observe the influence on the gas purities, being of special importance the improvements reachable in terms of hydrogen impurity levels on oxygen side.
Long-term tests have been developed, aimed to run the cell block as longer as possible without interruptions. The main results of these tests have been to define the best operation conditions for the new cell topology and assess the effects of the current density, temperatures, flows and gas purities in a broad range of conditions.
The electrolyser at Walqa has been coupled to the renewable energy system (635 kW wind energy and 100 kW photovoltaic), providing good performance in terms of fast reaction in stand-by mode operation, quick changes in loads and good operation of the control system.
7 Techno economic analysis
First, an analysis was made of the techno economic scenarios for the case base electrolyser (SoA, 3.5 MW from IHT). The cost breakdown of the system was provided by IHT. These information allowed at the end of the project to assess the economic impact of each progress achieved, related to the production cost of the system or its performance.
Two simplified scenarios were proposed in order to estimate, in a first approach, the impact of the coupled capital cost and performance factors on the levelled cost of hydrogen and then to compare the reference system with the optimized one. The scenarios were located in Germany, since this country is very proactive on electrolysis solutions for electricity storage and mobility:
• 1st scenario: H2 production & electricity market. In this scenario, the 3.5 MW electrolyser is operated according to the electricity price of the German Day Ahead Epex Spot Market. An optimization was done to define the price threshold under certain conditions above what it is better to shut down the H2 production considering the electricity price and also the involved operating time of the electrolyser.
• 2nd scenario: Green H2 & Wind electricity production. In this scenario, the 3.5 MW electrolyser is directly coupled to a wind farm composed of x turbines of 1 MW. The electricity produced is in priority converted into H2 to be sold as ‘green H2’ and the surplus can be sold to the Day Ahead Epex Spot market with or without incentive price (Premium) for wind electricity.
• 3rd scenario: When presented at the mid-term review, this 2nd scenario was rejected in favour of a ‘Power-to-Gas’ (PtG) scenario, identified by AREVA in charge of the Market studies, as a market segment well suited for the pressurized electrolysis.
H2 production & electricity market
In this scenario, the 3,5 MW electrolyser consumed the electricity purchased on the German Day ahead Epex Spot Market. An optimization was done considering a price threshold above what it is better to shut down the H2 production.
• Main input data:
o German Day ahead Epex Spot for 2010, 2011, 2012
o Fees and subscription cost to attend the market
o German electricity network taxes and charge (lower taxes for a electricity storage application with the removal of the EEG-umlage)
• Variable: market price threshold above what the electrolyser is shut down.
• Criteria of optimization: levelised cost of H2 for a plant life of 20 years and 8% discount rate.
• Simplified approach: no constrain on H2 storage or delivery
As a first result, the figure presents the levelized cost of H2, according to the market price threshold for the electrolyser of reference and for the targeted electrolyser (25% reduction on stack cost, 80% stack efficiency and +10% electrical yields).
In the reference case with high grid taxes (no storage application), the optimum leveled cost of H2 is 4,7 €/kg, obtained for a market price threshold of 55 €/MWh. The targeted electrolyser could reduce this cost to 3,6 €/kg meaning a 22% reduction.
Power to Gas
In the ELYGRID scenario, the PtG system is used to convert the surplus of electricity produced by wind turbines in hydrogen stored in the natural gas network (the concentration limit of H2 in this network will not be taken into account in this study). Considering that the wholesale market price reflects the consumer demand, a threshold price will be fixed above what the renewable electricity is sold to the electricity market and below what this energy is degraded or converted to hydrogen and injected to the gas network.
If today, the investment cost and operating cost of a Wind plant cannot be profitable if the market price is applied without founding, it is obvious that, hydrogen produced and sold to the natural gas network will need as well an incentive price, since 30 €/MWh will not be competitive except for an electricity market price lower than 20 €/MWh (Price of the NG x 0.7 efficiency of the electrolyser). The wind electricity in Germany, when the analysis was made, benefit from an incentive selling price. In fact, the investment and operating cost of a renewable energy plant cannot be profitable if the market price is applied. To promote the development of renewable energy, governments create feed-in tariff and the guaranty to sell the produced energy. In 2012, in order to begin the transition away from fixed price incentives and in order to fit the renewable electricity injection with the consumer demands, the EEG 2012 encourages the direct sale of renewable electricity on the spot market through the introduction of a market premium, equivalent to an additional payment to compensate the difference between the market price and feed-in tariff.
Moreover, the feed-in tariff rate and the management premium are supposed to decrease over time according to a digression schedule. For the needs of the simulation, a fix Premium payment of 50 €/MWh will be considered for the 20 years of plant life
The natural gas in Germany, has a current price of 30 €/MWh. Feed-in-tariffs for biogas exist, fixed at 110 €/MWh for plant of 0.5-5 MW and 60 €/MWh for plant of 5-20 MW. For the scenario, the incentive feed-in tariff of 110 €/MWh will be retained
The power of the wind farm will be fixed at 10 MW. In order to convert all the energy produced, the electrolyzer needs to have an equivalent capacity. This will be the condition for the first simulation and in the second one, the capacity of the electrolyzer will be considered as a parameter of optimization and will vary between 1 and 10 MW.
The second parameter of optimization, similar to both simulations is the values of market price threshold below which RE producer has to use PtG or degrade his production. It will vary in a range of 0-50 €/MWh.
For both simulations, the levelized profit of the system (PV) and the maximum investment cost of the electrolyzer are calculated
• For simulation 1, with the parameter of optimization: ‘market price threshold’:
o S1 reference: 10 MW Wind power plant without PtG
o S1 PtG 10MW: 10 MW Wind power plant with a 10 MW PtG
• For simulation 2, with the additional parameter of optimization: ‘electrolyzer capacity’:
o S2 PtG 1-10MW: 10 MW Wind plant with variable capacity of PtG
o For this simulation in particular, the maximum specific investment will be calculated for different capacity of the PtG system
The results of the different simulations showed that despite favourable hypothesis (reduction in taxes, incentive selling price), in the current electricity market, the period of time with negative or low prices on the electricity market is not long enough to amortize the investment in PtG solution even with the expected improvement aimed in the project.
8 Life Cycle Assessment
The goal of this point is to present an in-depth assessment of environmental impacts induced by the advanced alkaline water electrolysis systems in comparison to state-of-the-art systems. This LCA is compliant to ILCD and therefore also to ISO 14040 , 14044 and FC-HyGuide. Most of the relevant data derive from the partners in the EU research project “ELYGRID”.
Environmental assessments of hydrogen production have been subject in many studies. However, a review paper shows that most of these studies had an exclusive focus on Global Warming Potential (GWP). Little attention has been paid to evaluation of ecological effects of individual alkaline electrolysis constituents. Therefore, modelling of environmental impacts caused by an exchange of membranes was not possible in the past.
Life Cycle Assessment (LCA) is used as method for environmental assessment within this study. LCA involves environmental impacts over the entire lifetime of products or systems. Finally, the main aim of this point is to present key results of the LCA and to assess if the technological advancement of electrolysis systems leads to environmental improvement.
The LCA includes a comparative presentation of the environmental outcomes of three different electrolysis systems. A state-of-the-art of traditional electrolysis system is compared to advanced new cell systems.
• Reference is a state-of-the-art 3.5 MW electrolysis system using conventional membranes (system I).
• The second system (II) includes the advanced membrane instead of the traditional membrane. This system is assessed to evaluate the effects of changes on cell level solely.
• In addition, an advanced system, which is planned for commercial operation, including further Balance of Plant (BOP) improvement (redesign of mechanical components, infrastructure changes) is analyzed (system III)
All three systems within this assessment are compared on the basis of the functional unit. For our assessment the production of 1 kg H2 at 33 bar and 40 °C are considered as functional unit. A technical service life of 20 years is considered for all systems. FC Hy-Guide proposes the subdivision of hydrogen production systems in construction, operation, and end of life.
Two different operation scenarios are analyzed within this assessment. As ecological best case an operation with wind power is considered. On the other hand an operation with electricity grid mix is assessed as worst case. For both cases a nearly year-round operation with only five short stops and start-ups a year is assumed. The prospective real operation will probably have lower full-load hours, but is not clearly quantifiable by now.
Results for the selected environmental impact categories applied on the three system types and two scenarios as well as related to the functional unit of 1 kg H2 are defined. Beside absolute values of the entire systems, shares on construction, operation, and disposal are taken into account.
Potential Impact:
As ELYGRID project specifically has addressed the coupling of high pressure and high capacity alkaline electrolyser with wind energy, it is expected that the results from ELYGRID will have a considerable impact beyond the geographical and time scopes of the project, contributing to advances in answers related to the new typologies of electrolytic hydrogen adapted to maximum penetration of renewable energies, especially wind energy.
Application of the results should not only benefit the EU, but could specially contribute to soften the serious environmental problems coming from developing countries which need new clean energy technologies to supply the electricity needed to support their socio-economic development, compatible with the preservation of the environment. Besides, the improvements have been technically assessed on different levels (membrane, cell, balance of plant, control) but also on other transversal matters (market analysis, RCS and LCA) which also contribute to expecting a wide diversity of impacts at different levels.
The development of the ELYGRID project, through the individual improvements, tests, designs and analysis done, is expected to derive in some impacts at short-term, while the general approach and strategy followed shall have repercussion on a mid/long-term level.
Among the short-term impacts, the following must be noted:
• Reduce H2 production cost from electrolysis with RES to approach the objectives of the FCH JU.
• Efficiency improvements of an alkaline electrolysis cell in high power pressurized electrolysers for mass production of hydrogen from RES.
• Prototype testing to verify and qualify the technology and raise public acceptance.
• International relevance.
• Demonstrate the technology in order to favour new projects, developments, products and services.
• Consolidate the strategy for alkaline electrolysis technology deployment, including RCS and LCA aspects.
• Generate confidence in electrolysis as an efficient technology to produce electricity and hydrogen from RES.
• Promote technological knowledge in RES sector, especially wind energy, for replications.
After the results and experience obtained in the Elygrid project, and thanks to the achievement of the proposed objectives and results, some steps have been made to pave the way to the mid- and long-term impacts:
• Saving on fossil fuels in electric power generation, making it less vulnerable to future problems in the supply of these resources
• Decrease in the high levels of pollution stemming from the existing power plants
• Expansion of the European renewable energy industries beyond its borders
• To contribute to improve energy efficiency
• To support renewable energy markets, by providing electric grids infrastructure with energy storage capacity, suitable for a maximum penetration of variable and intermittent RES, providing grid services.
• To contribute to satisfy electrical energy demand in a self-sufficient cost-effective way, by providing abundant, clean, secure and affordable energy, whilst simultaneously achieving substantial reductions in greenhouse gas emissions to mitigate the potentially serious consequences of climate change.
• To promote the security of energy supplies for the European Union
• Contribute to the development of more flexible, reliable and cost-effective energy storage solutions that will support the progressive introduction of RES technologies
The participants in the Consortium are currently, or have been in the past, involved in numerous projects, European as well as national and regional. Moreover, they have been involved in the different areas of industry and know-how with which the project has a direct relation: alkaline electrolysers and renewable energies.
European dimension
The project results are expected also to contribute to the development of policies in the areas of energy efficiency, promotion of renewable energies, and distributed generation related to production of hydrogen from alkaline electrolysis. LCA has been carried out in order to compare and establish that the proposed integrated solutions are ecologically suited to compete with other more conventional commercial alternatives under a reasonable set of accepted environmental impact indicators. Setting up an industrial project with international scope, to get technical data for RSC aspects and legislation development, has to favour mechanisms to motivate public bodies towards hydrogen production from renewable energies, and help the implementation of green certificates, investment aid, tax exemptions or reductions, tax refunds and direct price support schemes. From this point on, technology maturation will be faster due to the creation of an incipient market in a natural way.
The ELYGRID project has assessed the regulations, codes and standards at European level in order to check if potential policies gaps could block the commercialization of these electrolysers in the short term. All the analysis of the different directives has shown that the manufacturers have all the information in an EU policy framework level in order to commercialize an electrolyser.
In the middle and long term, European and national support mechanisms to incentive hydrogen production from RES have to be created. These incentive mechanisms could include green certificates, investment aid, tax exemptions or reductions, tax refunds and direct price support schemes, and should consider the external costs of electricity produced from non-renewable energy sources and the impact of public support granted to electricity production normally used to encourage the development of renewable energies within the internal electricity market.
ELYGRID project has a triple European character. First, due to the diversity of European countries which are involved. Secondly, the project is applicable to all member countries of the European Union, since issues associated with clean electric power generation and energy storage are clearly beyond borders and so are the benefits arising from the realization of the project. Third, the expected results affect several areas which constitute important goals which are central to the European Union policies such as promoting environmental protection and energy saving, fighting climate change and maximizing the use of renewable energy and the independence of fossil fuels.
Broad market introduction, however, is often hampered by high initial costs and thus insufficient customer demand. Action at the European level is expected to be required to create markets of sufficient size to bring down the cost of better environmental performance technologies. In any case, the market orientation of the project has proved to be very useful to provide a continuous analysis of costs for each technology and development proposed. Having several industrial partners being part of the consortium has totally permitted keeping this orientation along the duration of the project.
The Green Paper – Towards a secure, sustainable and competitive European energy network – stablishes a new approach to energy network development, considering that it should become a central issue when implementing energy policy. The 20-20-20 objectives have to be implemented in an effective manner, and it should be addressed through programmes relating to public and private sectors. The paper also states that European research should direct its work to the following key drivers:
• the integration of renewable energy sources in the network;
• the transport of energy from resource-rich areas to consumption centres;
• the use of technologies for the decentralisation of energy production and intelligent networks;
• the use of energy coming from offshore wind farms
• the development of technologies for the transport and storage of CO2.
At this level, ELYGRID could be considered also has a step towards these objectives, as far as the research has provided useful to develop more know-how and new technologies and designs that could be implemented in the near future to provide grid services.
Commercial impact
During ELYGRID project several market studies have been analysed in order to provide insight of the commercial possibilities of the overall system, at the studied scale corresponding to the SoA electrolyser and the Elygrid design.
The studies started with a reminder of why energy storage is an essential part of the deployment of renewable energies. As renewables are deployed, there will be more variability and intermittency in power generation, resulting in an increased need for flexibility to both smooth renewable power flows and maintain a stable grid. Different possibilities are envisioned to provide the needed flexibility, such as:
• Grid interconnections (power, heat, cold, gas): improvements of T&D meshing to mitigate the local variability of intermitent renewables output (North Sea Supergrid, Medgrid, Tres Amigas, etc)
• Flexible fossil energy sources: oil or gas fired single cycle combustion turbines. Depending on geography and hydrography: hydro power plants
• Dispatchable renewable energy: pooling of micro-CHP units as balancing Virtual Power Plants, thanks to smart grids (Lichtblick, Bloom, etc)
• Demand-side management: contracted loads curtailments with commercial or residential customers, thanks to smart-grids (EnerNOC, Comverge, etc)
• Energy storage systems: use of energy storage to smooth renewable generation output and better serve the grid at peak (H2 storage but also flywheels, compressed air, flow batteries, etc)
Compared to other solutions, energy storage has the advantage of being versatile, however when it comes down to comparing costs, it has a clear disadvantage as it is still at early stage development. However, the increased need for flexibility, the limitations of pumped hydro, means there is room in the future for a competitive energy storage solution to emerge.
The energy storage market cannot be considered as a whole as it is specific to a region, an energetic and policy context, applications and needs. In order to understand the market potential for alkaline electrolysis coupled to renewables, therefore a segmentation market is proposed by region and application.
From the applications identified, ELYGRID should have more impact on the field of generation and economic optimization (direct link with renewables deployment). The first segment size at 2500MW in 2020 was identified equally split between Europe and USA, being the last one more difficult to access, in line with : NREL (USA) – The Value of Energy Storage for Grid Applications (May 2013), Imperial College (UK) – Strategic Assessment of the Role and Value of Energy Storage Systems in the UK Low Carbon Energy Future (June 2012)
Considering that hydrogen may be used as energy storage in several ways (to produce electricity, to produce liquid fuels and chemicals or to produce H2/CH4) the following conclusions about the potential impact on the market:
• Electricity-to-electricity solutions are not a path to pursue for alkaline electrolysis because it is an expensive solution with limited yield. Therefore, this option will need technology breakthroughs to be competitive with other flexible solutions. Some of the drawbacks are shown in the following:
o Intrinsically high technology costs (fuel cell membranes)
o Limited yield with 35-40% efficiency (raising energy price)
o Limited lifetime of the system
o Short response time, but no instantaneous
• PtL is only applicable at a large scale, with low energy costs and high value liquids
• PtG is also applicable at smaller scales, however the value of the gas generated is very challenging without subsidies. PtG is better thanks to its scalability and simplicity, but however there are still some drawbacks for PtL and PtG options:
o The liquids address to the fuel and chemical markets and are subject to their underlying commodity price volatility.
o Low value PtG gases. Unless self-consumed and access to gas grid is required.
o Low energy density of PtL output (DME 22 MJ/kg) [H2= 120, Gasoline=45, Diesel=34]
o Ptl and PtG rely on high cost electrolysers which would operate at part load, further challenging the economics
o Also, large scale flexible electrolyzers are not readily available
PtG can serve for several applications within 2 segments selected for alkaline electrolysis coupled to renewables.
The main conclusions of the market studies showed that several complementary action channels have to be activated to stimulate market emergence:
• Regulation
o Grid access: allow H2 injection to gas grid
o Blending targets: ensure dedicated share of “green” hydrogen into final products
o Subsidies: provide specific financial incentives for PtG (tax credits, FiT, depreciation)
• Technology
o Flexibility: focus research on alkaline electrolysis flexibility
o PEM size-up: focus research on PEM electrolysers size-up
o Hybridization: innovative with complementary hybrid systems: H2+flywheel, H2+ultracaps, etc
• Applications
o Market combination: with new technologies, explore new revenue combinations
o Tri-generation: explore H2-based tri-generation: power+heat+cold
o Micro H2 grids: transpose the smart building segment to microgrids&islands
To provide the long term impact at commercial level, one of the first steps is identifying the adequate stakeholders, enablers that have to be contacted when going to market strategy. Besides the public bodies and institutional sectors, there are other agents that are key to assure the commercial impact of this kind of solutions, like
• Grid operators
• Advisors: Research organizations/Energy markets
• Prospects: Utilities, IPPs, ESCo’s
As it has been stated before, the commercial plan for the overall Elygrid solution is expected to have a long-term development, especially taking into account the results and analysis regarding the market niches and the prospects from stakeholders for the technology.
Exploitation of the results
The project has a well oriented market approach with the clear leadership of the electrolyser manufacturer IHT. Having worked with an incremental and modular approach to the improvements has been useful to develop several designs that can be considered in pre-production phase. Since the very beginning of the project, the consortium has been oriented to merge the different developments of each partner in a potential advanced electrolyser at the end of the project.
By doing it, the results can be exploited in the easiest way by bilateral relationships between the electrolyser manufacturer and the partner in charge of the development. The further development or the decision of pursuing or continuing the line of work has to be decided individually by the partners or as joints developments, as it has been stated and granted by the Consortium Agreement on IPR issues. The assessment of potential commercial possibilities has been carried out during the project, and the potential impact at industrial level has to be pointed out for the developed solutions and the market prospective.
The following results obtained in the project could be included in a potential advanced electrolyser:
• Power electronics: Ingeteam has developed a power stack prototype that has passed the quality tests and has received the internal approval and readiness check-up for pre-manufacturing. On the other hand, the design made within the project renders the power stage apt for other market applications
• Membrane development: EMPA and VITO have been working on the development of new potential materials for using as membrane in an alkaline electrolyser. Both partners have identified potential industrial manufacturers interested on the market production of those materials at large scale
• Control system: Inycom, being participant on the control strategies definition, hardware installation and software development of the configuration, monitoring and control tool for the electrolyser, has established itself as a capable provider of technological solutions at industrial level, as far as this development can be used as part of their portfolio as showcase of the company’s R&D department abilities
• Mechanical equipments: Lapesa, as vessel separator manufacturer, has developed different units regarding the electrolyser as gas separators, head plates, tie rods and feet. These equipments have been designed according to the update pressure equipment directive
• Balance of plant design: FHA has designed a plug&play BOP for a mega watt alkaline electrolyser in a standard container. Besides, auxiliary units as water supply system and purification unit have been also designed in accordance with the operation conditions defined in the project.
To summarize, the project has been success on testing a new cell topology with 70% stack efficiency, design a new BOP electrolyser with a capacity of 2.98 t/d and with a global cost of much less than the FCH2-JU objective for 2020 of 2M€/(t/d).
Dissemination activities
From the beginning of the project, and in order to achieve also the expected impact on different public and communities, the dissemination activities were planned as key to reach the public and stakeholders. More specifically, the actions planned were the following:
• Development and maintenance of the website in order to reach to the technical community and the general public, to communicate the advances in the project and the results.
• Publication of the results in specialized magazines and scientific journals.
• Elaboration of a press kit.
• Presentation in specialized international and national conferences and events, such as the annual FCH-JU General Assembly.
• Guided visits to the testing facilities.
• Workshops or events, oriented to the participation of industrial and stakeholders interested on the technology, but also general public to show them about the benefices of renewable energy and hydrogen storage technologies.
The project has been presented to 21 conferences. FHA has been the main attendant to the conferences as project coordinator but it has been remarkable the efforts done by EMPA and JÜLICH to disseminate their results. The complete list of the conferences has been uploaded to this document.
The appearance in mass media has been framed to the launch of the press release at the beginning of the project by the FHA and an event attended by the FHA in June (2014). There has been another press release announced the end of the project, the main results and the final event together with the RESelyser project.
Regarding publications, the Elygrid project has been more oriented to provide solutions and technology to the electrolyser manufacturing sector rather than develop scientific material to public disseminations. It is important to remark that confidentiality matters have been taken into consideration when some public scientific communication has been proposed by a partner.
Most of the partners have been focused on including their developments in the potential MW electrolyser and for this reason it has been considered more appropriate to limit the communication in aspects such as membrane development (VITO, EMPA), cell topology (IHT), power electronics design (INGETEAM), control development (INYCOM) or new BOP design (FHA). The main publications are related to the modeling of the BOP and the Life Cycle Assessment. There has been just an article based on a LCA review published in a peer-review journal but other articles in LCA, modeling and safety risk analysis have been prepared and they are under revision nowadays.
The project has also been presented in events and workshops with stakeholders. The project was presented in the workshop organized by the FCH-JU/NOW called “Electrolysis day”, by an oral presentation done by FHA. At the end of the project, FHA has organized two different events to make diffusion of the results and a continuation plan of the project. A joint workshop was presented as a technical meeting together with RESelyser project in order to share public results and try to look for further collaboration between the different partners. The other event has been the presentation of the results to all the FHA stakeholders (more than 60 companies) in the general governing board. It is considered very important as some of these companies could have potential interest in the results obtained in the project as potential end-users of the technology. These companies are summarized below:
• Endesa -> Spanish utility (electricity and gas)
• Iberdrola Renewable -> Spanish utility (electricity and gas)
• RWE Innogy Aersa -> owner and promoter wind farms
• Wind Energy Promotion Association, Aragon Wind Energy Company, Aragon Wind Energy Association -> three different associations with interest in the further deployment of wind energy at local and national level
• Enhol Group -> owner and promoter wind farms
• Taim Weser -> promoter wind farms
• Gamesa Energy -> promoter wind farms
The website has been the other driver for communication and dissemination activity. It has been periodically updated with the presentations done by the different partners and with news related to the topic.
The website has been regularly visited. The total amount of visits has been 65.506 skipped between the different years. There have been more visits during the last two years of the project once the communication activities have been progressively increasing.
It is especially interesting to know the high ratio of visits from North America, showing the potential interests of this technology in the USA market. It could be related to the growing interest of methanation process in USA, where large amounts of hydrogen are needed to produce syngas. If this classification is done by countries, it can be seen as obviously the main contributor to North American visits is USA and Germany, Russia, UK, France and Spain in Europe.
As final remark of the dissemination activities, it can be concluded that they have been fruitful reaching to different publics through the adequate media, and it has been possible to make contact with stakeholders and technological agents implied in the energy, renewable energy and hydrogen sectors. As drawback, the commercial or industrial orientation of the project has caused that the scientific production has been limited, mainly due to IPR issues.
List of Websites:
Project website:
www.elygrid.com
Coordinator contact details:
Fundación para el Desarrollo de las Nuevas Tecnologías del Hidrógeno en Aragón
Ctra. Zaragoza, N330A, km 566, 22197. Cuarte (Huesca)
info@hidrogenoaragon.org
