Hydrogen storage alloys for stationary applications

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• An alternative option to store hydrogen in a more compact and safer way than compressed gas systems, applied to a hybrid H2 – Li-ion Power-to-Power plant built in an off-grid site. In off grid locations the energy supply has always been a problem in terms of infrastructures and costs. Power-to-Power (P2P) energy systems could assume an important role especially in these sites, in order to make these places energetically independent and mostly based on renewable sources exploitation. P2P have in fact a great potential to help fixing the problem of intermittent production of RES like wind and PV. This paper aims to describe a real hybrid H 2 -battery P2P system with special focus on the topic of hydrogen storage. Today, H 2 is conventionally stored in high-pressurized vessels and this solution is linked to several technical and regulatory problems (encumbrance, safety, metal embrittlement, too large volumes going above regulatory limits in some cases, etc.). Instead, hydrogen can be absorbed in large quantities using metal hydrides, reaching volumetric density values often higher than liquid hydrogen. Discovered in the late 70 s and extensively studied in the last decades, this kind of solution has never reached a proper commercialization principally due to the limited gravimetric density values, making them unsuitable for automotive and transport purposes. But hydrogen storage alloys (HSA) can raise significant interest for stationary applications. Two of the most promising alloys are considered as applicable in a real P2P plant that will be built in Italy (Ginostra – Sicily) in the framework of the H2020 project REMOTE, modelled, designed and compared to the state-of-the-art solution based on a compressed hydrogen vessel. The final part of the paper covers the preliminary economic assessment of this new kind of plant and a future (optimistic) price trend, plotting a hypothetic learning curve.