Reversible Power-to-Gas systems for energy conversion and storage

Reversible Power-to-Gas systems can convert electricity to hydrogen at times of ample and inexpensive power supply and operate in reverse to deliver electricity during times when power is relatively scarce. Here, the authors show that such systems can already be economically viable relative to current hydrogen prices in the context of the German and Texas electricity markets. In the transition to decarbonized energy systems, Power-to-Gas (PtG) processes have the potential to connect the existing markets for electricity and hydrogen. Specifically, reversible PtG systems can convert electricity to hydrogen at times of ample power supply, yet they can also operate in the reverse direction to deliver electricity during times when power is relatively scarce. Here we develop a model for determining when reversible PtG systems are economically viable. We apply the model to the current market environment in both Germany and Texas and find that the reversibility feature of unitized regenerative fuel cells (solid oxide) makes them already cost-competitive at current hydrogen prices, provided the fluctuations in electricity prices are as pronounced as currently observed in Texas. We further project that, due to their inherent flexibility, reversible PtG systems would remain economically viable at substantially lower hydrogen prices in the future, provided recent technological trends continue over the coming decade.

Automated summary

The authors demonstrate that reversible Power-to-Gas systems are economically viable in the German and Texas electricity markets. These systems can convert electricity to hydrogen during times of ample power supply and operate in reverse to deliver electricity when power is scarce. The model analysis shows that unitized regenerative fuel cells with reversibility feature are already cost-competitive at current hydrogen prices, and they are projected to remain economically viable even with substantially lower hydrogen prices in the future.