A French research project has provisionally concluded using methane in a closed-loop power-to-gas-to-power (P2G2P) process could be a “credible solution” for seasonal storage from 2030.
The FluidSTORY project is looking into the viability of an electrolysis-methanation-oxyfuel (EMO) cycle for P2G2P, using underground storage for methane, carbon dioxide and oxygen.
EMO aims to overcome an important challenge with conventional power-to-methane: the fact that carbon dioxide supplies, say from carbon capture and storage, may be insufficient for methanation.
To deal with this, the carbon dioxide used in EMO is stored underground, in salt caverns, and cycled in a closed loop, so it can be reused endlessly.
There are other differences between EMO and the standard power-to-methane process, where hydrogen is transformed into methane, using biological or catalyst-based methanation, with the addition of carbon monoxide or dioxide.