From biomass and electrolytic hydrogen to substitute natural gas and power: The issue of intermediate gas storages

The possibility to upgrade biomass and intermittent power from renewable energy sources generating stable power and substitute natural gas (SNG) has been discussed in previous papers. Such papers focussed mainly on the choice and design of the most suitable power units to generate power and a high purity carbon dioxide stream to feed the methanation section; moreover, heat recovery strategies to improve the plant efficiency were investigated and implemented. In the proposed plant, power for electrolysis potentially comes from renewable energy sources (RES), thus arises the need to introduce gas storages in order to fully decouple the outputs (SNG flow and stable electric power) from the input intermittency. This paper analyses some different possible layouts for intermediate gas storages and compares them from an energy consumption point of view.