Two years ago, SoCalGas partnered with Electrochaea, a green tech startup developing a new biomethanation technology. Our goal was to help Electrochaea commission the first biomethanation reactor system in the U.S. at the Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado. Now, energy technology company Baker Hughes is taking a 15% stake in Electrochaea and plans to adopt their technology.
A biomethanation reactor system uses renewable electricity to convert hydrogen into biomethane (also called renewable natural gas RNG). The RNG can replace traditional natural gas and be used in homes, businesses, and in transportation and be distributed through natural gas pipelines. Electrochaea’s system builds on a pilot test of power-to-gas technology at NREL that began with help from SoCalGas in 2017.
The bioreactor uses an ancient microorganism, archaea, that feeds on renewable hydrogen and carbon dioxide. The microscopic heat-loving bacteria convert the hydrogen and carbon dioxide to pipeline-quality methane, creating a supply of RNG.
RNG is created through this bioreactor system in a two-step process. First, renewable electricity passes through an electrolyzer where water molecules are split into hydrogen and oxygen, storing the renewable electricity as hydrogen gas. Then, the newly-created hydrogen is combined with carbon dioxide and piped into the reactor where the microorganisms produce RNG.
The system is capable of recycling carbon dioxide from numerous sources, such as ethanol plants and anaerobic digesters, preventing greenhouse gas emissions and replacing the use of fossil-based methane. The team is working to make the system less expensive and more energy-efficient. In 2019, a bioreactor demonstration at NREL successfully demonstrated over 97% conversion of CO2 and hydrogen into RNG.
The next phase of the project will focus on improving the process efficiency by operating at higher pressures, automating plant operations, reducing capital costs and identifying locations in the western U.S., including California, where grid-scale energy storage would be most beneficial and cost-effective.
New technologies like biomethanation are part of SoCalGas' plan to help California achieve its ambitious climate goals and support our vision to build the cleanest, safest and most innovative energy company in America.