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Molten Salt Loop 2.0: key element for the new solar thermal energy plants.

Periodic Reporting for period 2 - MSLOOP 2.0 (Molten Salt Loop 2.0: key element for the new solar thermal energy plants.)

Reporting period: 2018-02-01 to 2019-07-31

Wide Solar Thermal Electricity (STE) market, generated by Concentrating Solar Power (CSP), is a reality today with 5.5 GW in operation worldwide in 2018 - is expected to more than double over the next decade, 260 GW in 2030, 664GW in 2040 and to reach a 12% of total electricity generation by 2050 (982 GW). This forecast has been reinforced recently after the truly historic Paris Agreement at Convention on Climate Change in Paris (COP21) where it was acknowledged that deep reductions in global emissions will be required to achieve a reduction of global greenhouse gas. STE technology can provide reliable energy supply and reduce CO2 emissions. Currently, there are 7,390 MW planned and announced for CSP plants projects in the forthcoming years. The investment foreseen to cover this growth will be over €16 billion in 2020. It is expected to save 1.2 billion tonnes in 2050.
Despite this encouraging scenario, CSP growth has been slower than expected because several issues have not been overcome yet. It is not as cost-efficient as other technologies making difficult its access to the generation mix. Its low cost-competitiveness comes from the need of a large up-front investment to deploy CSP plants in comparison with conventional energy plants or other renewable facilities. Another not-solved aspect is flexibility, since one of the main issues of the electrical market is the complexity to match the supply and demand curves due to the arbitrariness of the sun. Finally, some CSP technologies bring some environmental issues. In current CSP plants, soil, groundwater and surface water, air and human presence could be affected by leaks or emissions of synthetic oil used as HTF (heat transfer fluid). Furthermore, specifically, CSP plants need a meaningful amount of water to operate since are often designed to use water for cooling at the back-end of the thermal cycle. These water requirements can result in difficulties in arid areas, e.g. in the Middle East & North Africa (MENA) region, being the region in the world experiencing the hardest water stress.
In this framework, MSLOOP project was born to offer an innovative solution to overcome the mentioned barriers. The objective of MSLOOP is to validate a business opportunity consisting of developing a cost effective solar field for CSP Parabolic Trough Power Plants using optimized ternary molten salts as HTF with an innovative hybridization system. The result of the project is a new solution of CSP commercial plant with a levelized cost of energy reduction and capable of providing firm and dispatchable electricity through a hybrid plant concept and more environmentally sustainable than the deployed CSP technologies.
The starting point of the project was the integration of two prototypes: 500 m loop representative of a solar field (LAZOSALES) connected to a hybridization system (HYSOL); both combine synergies to succeed in achieving the objectives of increasing flexibility of energy dispatch at a competitive cost. With this basis, MSLOOP proved the increase in cost-competitiveness in terms of CAPEX and OPEX by carrying out innovative solutions that make the technology more reliable. MSLOOP is configured to make possible the integration of a hybrid plant concept, providing firm and dispatchable electricity using 100% renewable energy sources. MSLOOP eliminates the oil issues by using an environmentally friendlier HTF and has reduced the water consumption without penalizing the CSP plant performance.
The work carried out from the beginning to the end of the project has covered all the steps to obtain a marketable technology. WP2 was focused in developing the concept design and basic engineering of the aspects that needed to be improved to make the technology more reliable. The elements to be developed were the ternary molten salts additives and a real time measuring system to know the composition of the mix during the operation, the heat collector elements needed for an optimal operation of the plant, the collector structural analysis, the operation modes of the prototype, the solar field auxiliary systems needed to provide reliability to the operation and the water consumption reduction.
WP3 consisted in detailing the characteristics of the elements and systems analysed in WP2 by carrying out the detail engineering: data sheets, diagrams, plans, and operation manuals of the systems and components to be installed in the prototype. Once this documentation was crated the next step consisted in manufacturing and supplying the required elements that would be installed in the prototype.
The first step of the WP4 consisted in commissioning the equipment (new developments and former systems of the prototype) to set-up the individual parameters according to the new operation modes and the results of the simulations. Once the installation was prepared to carry out the test with the required guarantees the operational tests were carried out. The empirical results were compared to the simulations and operation models were updated and validated with real operation conclusions. Certifications were issued by accredited bodies for the heat collector element and the tests carried out in the prototype and the laboratory of UCM.
Once validated, the technology was scaled up from prototype scale to commercial scale (WP5). Four case studies were chosen according to the market analysis and the possibilities that the MSLOOP offers: a 12 MW plant in Sicily (Italy), the same location including HYSOL, and 80 MW in Northern Cape (RSA) with and without HYSOL. These designs allowed the dimensioning and evaluation of CAPEX and OPEX which combined with the energy production the LCOE and firmness of energy supply (in which percentage the energy demand is satisfied) were obtained so the consortium could compare MSLOOP with alternative technologies.
Other important aspects were also analysed during this stage: LCA of the molten salts and comparison with alternative HTF fluids, identification of the critical equipment, material degradation, maintenance to be carried out and health and safety issues. All these inputs were taken into account to make a comparison with other RES.
Finally, WP6 was focused in the business model and exploitation. The consortium carried out a study of the bankability process, stablished the commercial strategies and market analysis and developed a business model and exploitation plan.
The project management and dissemination activities have been performed according to the different technical stages.
After the project execution, it can be claimed that the main progresses that have been achieved during the project are the technical developments (molten salts additives, monitoring system, solar field auxiliary systems, operation, production, financial models and heat collector element optimized to perform under the MSLOOP parameters) that provide the reliability to achieve a technological readiness level enough to be deployed at commercial stage. The systems developed, the experience gained during the commissioning and the tests performed in the prototype are a proof for investors and developers to reduce the technical uncertainty that new technologies entail.
The results obtained allow the members of the consortium to offer a new solution in future CSP tenders by providing a cost competitive technology with a high level of flexibility in the energy supply and with no environmental drawbacks.
Project Leaflet
Project poster
Presentation of MSLOOP 2.0 in SOLARPACES 2017