Southern California Gas Company (SoCalGas), National Renewable Energy Laboratory (NREL) and the National Fuel Cell Research Center (NFCRC) collaboratively launch demonstration projects to create hydrogen gas from carbon-free renewable energies, such as solar and wind, for storing. The so-called “power-to-gas” technology converts electricity into gaseous energy and could provide North America with a large-scale, cost-effective solution for storing excess energy produced from renewable sources.

Using electrolyzer-based methods, the power-to-gas concept uses electricity from renewable sources, such as solar and wind power, to make carbon-free hydrogen gas by breaking down water into hydrogen and oxygen. The hydrogen can then be converted to synthetic, renewable methane — traditional natural gas — and stored to meet future energy needs. It can also be used as a multi-purpose energy source for vehicles, micro-turbines, fuel cells or other equipment.

"A power-to-gas system can help California meet environmentally-focused energy goals and solve a major energy challenge facing our nation: how to cost-effectively store excess power from renewables to meet energy demands when the wind does not blow or the sun does not shine," said Patrick Lee, senior vice president, customer service, innovation and business strategy for SoCalGas.

California is expected to produce 33% of its electricity from renewable sources within five years and Gov. Jerry Brown's new energy goals call for significantly increasing that level to 50% by 2030. As the amount of power produced from renewable resources increases, storing it for later use is a worldwide challenge. Batteries, a standard form of storage, require significant capital investment, but have limited capacity and relatively short duration.

Commercial-scale power-to-gas systems are already used in Germany and are being explored globally as a means to convert and store increasing levels of wind and solar power during times of excess supply. Such a commercial system could enable natural gas utilities across North America to use their existing pipeline infrastructure as essentially a large, cost-effective "battery" to store and deliver clean, renewable energy on demand.

Located at the NFCRC at the University of California, Irvine and NREL's laboratories in Golden, Colorado, the power-to-gas demonstrations will also assess the feasibility and potential benefits of using the natural gas pipeline system to store PV and wind-produced energy. If people can store the electricity generated by renewable resources in a cost-effective way, it would help prompt alternative energy worldwide, pointed out Dr. Martha Symko-Davies, the Director of Partnerships for Energy Systems Integration for NREL.

While much attention has been focused on developing batteries to store excess energy, battery capabilities are still limited to short-term storage and batteries remain expensive. Power-to-gas offers longer term storage capacity and cost-effectively using existing natural gas infrastructure to potentially create the world's largest storage technology. In addition, power-to-gas storage can conserve the significant amount of energy currently wasted when renewable production exceeds consumption.

"With the extensive storage capacity of natural gas infrastructure, this project will provide important validation of the technical and economic feasibility of carbon-free energy transformation and storage," said Professor Scott Samuelsen, director of the NFCRC.

SoCalGas' power-to-gas project is expected to provide valuable data on the dynamics of hydrogen production in a system flush with renewable electricity. Initial project results are expected by year end.

(Photo Source: SoCalGas)