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COmbined hybrid Solution of Multiple HYdrogen Compressors for decentralised energy storage and refuelling stations

Periodic Reporting for period 1 - COSMHYC (COmbined hybrid Solution of Multiple HYdrogen Compressors for decentralised energy storage and refuelling stations)

Reporting period: 2017-01-01 to 2018-06-30

Hydrogen mobility is a promising solution to achieve a sustainable energy transition in the transport sector. Ease of use, speed and efficiency of the refuelling process are essential for the successful adoption of hydrogen in transport. Fuel Cell Electric Vehicle (FCEVs) use hydrogen stored in a pressurized tank and are fuelled with gaseous hydrogen at pressures of 350 or 700 bar. Therefore, hydrogen compression is a key component of the refuelling process and costs reduction and efficiency improvements of the compression step are crucial for the success of hydrogen mobility. COSMHYC tackles this challenge in order to significantly contribute to the recently started rollout of hydrogen passenger cars, busses and trains.
The consortium is developing and testing a new compression solution for hydrogen refuelling stations for fuel cells passenger cars, busses and trains. The technology can also be used for refilling of compressed hydrogen trailers. This new solution combines an innovative compression technology with a mechanical compressor while optimizing both technologies for a compression from 1 to 1000 bar. The innovative compression technology is using a thermo-chemical process in which the hydrogen is interacting with alloys to form compounds named hydrides. One objective of the project is to identify and select the alloys with the best properties and the best composition.
The overall objectives of the project are to lower investment and operational costs, to reduce the noise level related to the mechanical compressor, to increase the availability of stations, and thus to increase the efficiency of hydrogen delivery. At the level of the compression process the energy efficiency will be increased by at least 20%, by optimizing interactions between both compression technologies. Thanks to the triple effect of energy efficiency, reduction of investments costs (down to less than 2000 €/(kg*day)) and maintenance optimization (reduced by 50% compared to mechanical compressors), COSMHYC will lead to an overall reduction by 20% of the hydrogen costs at the refuelling station. In addition, the noise disturbance will be significantly reduced compared to existing mechanical compressors.
COSMHYC started in 2017 with the precise definition of technical requirements for the compression solution for selected applications: refuelling of FC cars, busses and trains, refilling of compressed hydrogen trailers. Also, economic parameters were considered from the beginning of the project to conceive a compression solution which will be competitive. Later in the project, additional techno-economic assessment will be conducted by the partner LBST to ensure this objective.
Significant achievements were reached during the first phase of the project.
• An extensive analysis of metal hydrides was performed and led to the successful selection of rare earth free metal hydrides. This strong achievement is an important milestone, ensuring the core performance of the new COSMHYC compression solution.
• A metal hydride compression reactor was successfully designed to enable a wide range of operations, from a thermal and mechanical point of view. The achievable flow rate was increased by a factor 10 compared to the state-of-art.
• Detailed activities took place for designing the innovative metal hydride compressor, including the system integration concept. In addition, safety and pre-certification activities have been performed.
• Finally, major improvements in terms of efficiency and lifetime were achieved on the mechanical compressor. An operating temperature reduction from 250°C to 150°C has been successfully demonstrated. Also, significant life time improvements have been demonstrated at the modelling scale by the use of innovative materials. The construction of the mechanical compressor prototype has been initiated.
MAHYTEC, EIFER and NEL are currently developing the compressors and focussing on the integration of both technologies, which will be tested in a comprehensive way.
For the innovative metal hydride technology, the selection of three metal hydride without rare earth but with appropriate performances is a significant step beyond the state of the art. Indeed existing metal hydride compressor prototypes are still using rare earth elements, showing poor heat transfer capacity, limited flow rate or high energy consumption. The new hydrides, selected by partner MAHYTEC, have very promising characteristics and are well adapted to the needs of the COSMHYC project. Additional tests will be performed in order to definitively validate the selection of hydrides. The innovative design of metal hydride reactors enables a change of scale by a factor 10 compared to the state-of-art.
Also, the advances on the mechanical compressors result in performances which are far beyond existing mechanical compressors and are compatible with a wide deployment of hydrogen mobility. Latest developments of NEL demonstrate that a noise target below 65DB can be reached, when state of the art mechanical compressor are much louder (85 DB).
The joint efforts on two compression technologies, mechanical compression and an innovative metal hydride compressing technology without moving parts, within the same project will enable to exploit the synergies between both technologies for achieving various compression levels. This modular scalability is an innovative feature of the COSMYC solution. This hybrid approach will enable to reach peak flow rates of up to 60 kg/h from 450 bar to 1000 bar, compatible with the requirement of typical hydrogen refuelling stations. Such flow rates would not be reachable at reasonable costs with a non-mechanical compressor. This will have a significant positive impact on the future costs of refuelling stations.
Thanks to the hydride solution, the electricity consumption of the COSMHYC hybrid compressor will lower electricity consumption below 1.5 kW h/kg, when state of the art compressors need at least 3 kWh/kg. This will result in specific costs around 2 k€/kg*day for the COSMHYC hybrid compressor when state of the art compressors are in the range of 5 to 12 k€/kg*day.
Crank case of the mechanical compressor
Principle of the COSMHYC compression concept