It is widely recognized that today’s great challenges of the human being are dealing with the mitigation of climate change and the safe access to low-cost energy sources and carriers. The expansion of the use of Renewable Energy Sources (RES) is a priority. However, maximizing the RES penetration in our energy systems for the production of energy vectors, such as electricity and hydrogen, requires the solution of technical issues to cope with the intermittency of the (non-programmable) sources, seasonal variations, need for storage, balance/management of the grids, security of supply and low-cost of power and hydrogen production. Some technology solutions exist (e.g. photovoltaic and concentrating solar systems for power and heat generation, energy storage systems, electrolyzers) but their combination to best achieve the above objectives has to be developed and demonstrated.
Green hydrogen production at low-cost will foster the decarbonization of hard-to-abate industrial sectors (e.g. the chemical, steel, fertilizer industry); hydrogen can replace natural gas in the gas infrastructure and also improve the management of power grids with increasing RES footprint.
In this context, the project PROMETEO proposes a solution for green hydrogen production from renewable heat & power sources by high temperature electrolysis in areas of low electricity prices associated to photovoltaic or wind.
Solid Oxide Electrolysis (SOE) is a highly efficient technology to convert heat & power into hydrogen from water usually validated in steady-state operation. However, the heat for steam generation may not be available for the operation of the SOE when inexpensive power is offered (e.g. off-grid peak, photovoltaics or wind). Thus, the challenge is to optimize the coupling of the SOE with two intermittent sources: non-programmable renewable electricity and high-temperature solar heat from Concentrating Solar (CS) systems with Thermal Energy Storage (TES) to supply solar heat when power is made available.
In PROMETEO a fully integrated optimized system will be developed, where the SOE combined with the TES and ancillary components will efficiently convert intermittent heat & power sources to hydrogen. The design will satisfy different criteria: end-users’ needs, sustainability aspects, regulatory & safety concerns, scale-up and engineering issues.
A fully-equipped modular prototype with at least 25 kWe SOE (about 15 kg/day hydrogen production) and TES will be designed, built, connected to representative external power/heat sources and validated in real context (TRL 5). Particular attention will be given to partial load operation, transients and hot stand-by periods.
Industrial end-users will lead to techno-economic and sustainability studies to apply the technology in on-grid and off-grid scenarios and for different end-uses: utility for grid balancing, power-to-gas, and hydrogen as feedstock for the fertilizer and chemical industry.
