Reversible fuel cells for backup power generation

Researchers at Stanford University in the United States and at the University of Mannheim in Germany have proposed using reversible fuel cells as backup power generators to cope with volatility in electricity markets and pronounced fluctuations in power prices.

“Reversible fuel cells can be an economically viable source of backup electricity during periods of surging prices, such as Texas experienced in 2021 when winter storms knocked out power plants fueled by natural gas,” the research's main author, Stefan J. Reichelstein, said, noting that reversible systems can help get economic value from renewable electricity when prices are low.

In the paper Reversible Power-to-Gas systems for energy conversion and storage, published in nature communications, Reichelstein and his colleagues developed an analytical model of the unit economics of the reversible fuel cell system. “While modular systems require sufficiently low hydrogen prices in order for the reversibility feature to be valuable, integrated systems can be economically viable for higher hydrogen prices by primarily generating hydrogen but also providing electricity during times of limited power supply,” the study reads.

Through the proposed model, which mainly considered the electricity markets in Germany and Texas, the research group found that fuel cell systems based on solid oxide cell (SOC) technology may be competitive at current hydrogen prices, provided that there is sufficient variation in daily electricity prices, as in the Texas market.

The reversible systems are said to be economically viable even in the presence of substantially lower hydrogen prices in the future. “This is because the inherent flexibility in these systems enables them to respond to lower hydrogen prices by operating more frequently in reverse mode, delivering additional electricity to the power markets,” the researchers said.

They also took into account the potential drop in costs for SOC fuel cells over the next 10 years and found that they may still be competitive even with substantially lower hydrogen prices. These systems may become particularly valuable during periods of electricity scarcity, including regular demand peaks and irregular supply shocks. “The reversible systems can be built to almost any scale, they add, so they can be used by individual companies or small communities as well as by large urban power grids,” Reichelstein concluded.