Optimizing energy production is a key part of the efforts in favor of the energy transition. This concern also applies to the energy consumption required for its transport and distribution. However, the reverse-flow station, a solution emblematic of research and innovation efforts to promote the emergence of new gases, is itself a major consumer of energy.
A challenge for RICE: to make the process as neutral as possible, by offsetting or, better, recovering the energy consumed.
The reverse-flow station features a compression function for raising the gas to high pressure so that it can be returned to the transmission network. During this phase, the compressor consumes energy.
On the other hand, especially in winter, when the biomethane produced is fully consumed, natural gas takes over. The molecules coming from the transmission network are then decompressed in the expansion station. During decompression, some energy is lost.
Our teams had the idea of attempting to balance this dual process by trying to recover the energy from gas expansion (in the high consumption phase), and converting it into electricity, in order to reuse it during the biomethane compression phase (in periods of low consumption).
Although it is possible to use existing solutions, i.e. a compressor and a pressure reducer equipped with a turbine to recover energy, we decided to work on a solution that would combine these two technologies in a single, now non-existent one.
This would allow the compressor to operate in both directions. This would be in the traditional electricity-consuming way in the biomethane recovery phase, but in reverse during high consumption periods, allowing the gas flow to produce electricity via a generator.
The project is still in the theoretical phase; the functioning and possible yields of such a solution are being evaluated. Once this phase has been validated, a prototype will be able to be manufactured and tested on the test benches of our Alfortville station.
A win-win streamlining solution.