Southern California Gas Co., the National Renewable Energy Laboratory (NREL), and the National Fuel Cell Research Center (NFCRC) have teamed up to launch the first power-to-gas demonstration projects in the U.S. The two facilities will be located at the NFCRC at the University of California, Irvine and at NREL headquarters in Golden, Colo.

Power-to-gas technology involves using electrolysis to convert water to hydrogen, and a methanation process to combine hydrogen with carbon dioxide to generate synthetic methane. The approach has drawn attention as a means of storing excess renewable energy in a way that would leverage existing natural gas infrastructure and generation. Rather than storing overgeneration as electricity, it would be converted to methane and injected into natural gas pipelines, potentially allowing storage of far more energy than is currently possible with other non-hydro energy storage methods.

Around 20 to 30 power-to-gas projects are in development or have been launched in Germany and elsewhere in Europe, but deployed systems are small (<10 MW) and the economics of large-scale methanation are uncertain—synthetic methane is still far more expensive than natural gas. The NREL and NFCRC projects will assess both methanation technologies and the feasibility of using natural gas infrastructure to store excess renewable energy.

California was chosen for one project site in part because of the state’s large renewable energy mandate—potentially increasing to 50% by 2030—and its recent mandate to deploy 1.3 GW of energy storage by 2020.

“As we reach high levels of renewable energy on the grid, storing the electricity generated by solar power and other variable energy sources will help unlock greater use of these renewable resources,” Martha Symko-Davies, NREL’s director of partnerships for energy systems integration, said. “This project will examine a unique way to reduce the capital cost of energy storage.”

Initial project results are expected by the end of 2015.

—Thomas W. Overton, JD is a POWER associate editor (@thomas_overton, @POWERmagazine).