In the United States, Southern California Gas Co. (SoCalGas) and Opus 12 have recently announced the successful demonstration of a process to convert the carbon dioxide (CO2) in raw biogas to methane (CH4) in a single electrochemical step, dubbed "a critical improvement" in the upgrading of biogas to pipeline quality natural gas, and a simpler method of converting excess renewable electricity into storable natural gas.
Opus 12, a US-based clean-energy startup incubated in the Cyclotron Road program at Lawrence Berkeley National Laboratory, California, used a new type of Polymer Electrolyte Membrane (PEM) electrolyzer to convert carbon dioxide (CO2) to methane (CH4), showing that instead of wasting the CO2 in raw biogas, it can be converted to methane using renewable electricity.
This groundbreaking innovation holds the potential to simplify storing renewable electricity in the form of zero-carbon renewable natural gas that can be used for home heating, water heaters, or clean trucks to transport goods. Across Southern California, people prefer natural gas four to one over electricity because it is more affordable and reliable. Technological advances like this are one more example of how we can protect the environment while protecting consumer choice, said Yuri Freedman, Senior Director of Business Development at SoCalGas.
Los Angeles headed Southern California Gas Co. (SoCalGas), a subsidiary of San Diego headed holding company Sempra Energy, is the largest natural gas distribution utility in the United States. The research is part of SoCalGas’ development of power-to-gas (P2G) technologies as a method of storing excess renewable energy.
Because gases can be easily stored for long periods of time using existing infrastructure, power-to-gas technology has two distinct advantages over storing renewable electricity in batteries. The nine-month study was funded by SoCalGas along with two start-up-funding organizations, the Rocket Fund of Caltech’s FLOW program and Elemental Excelerator.
Southern California has ideal conditions for this type of solution, with significant biogas resources and high penetration of renewable electricity. SoCalGas has identified this regional advantage, and with their scale and expertise in P2G and biogas, the company has been the ideal partner for this project, said Nicholas Flanders, CEO at Opus 12.
Raw biogas is mostly methane, but also contains about 30 to 40 percent CO2, which is typically vented to atmosphere in a biogas production facility. While other power-to-gas systems convert water into hydrogen and oxygen using renewable electricity, Opus 12’s method would likely be implemented adjacent to biogas production so it can make use of a greenhouse gas (GHG) that would otherwise contribute to climate change.
This feasibility study was the first phase of research that will also explore new catalysts, modifying the catalyst layer formulation, and other ways to enhance the system’s methane conversion performance.