SoCalGas and Opus 12 develop technology to convert CO2 to methane

Apr 27 2018

A new electrolyzer technology can convert the unwanted carbon dioxide in raw biogas directly to pipeline quality natural gas using renewable electricity, simplifying the process of storing surplus renewable electricity as renewable natural gas.

The companies have successfully demonstrated the new process to convert the carbon dioxide in raw biogas to methane in a single electrochemical step, a critical improvement in the science of upgrading biogas to pipeline quality natural gas, and a simpler method of converting excess renewable electricity into storable natural gas.

Opus 12, a clean-energy startup incubated in the prestigious Cyclotron Road program at Lawrence Berkeley National Lab, used a new type of Polymer Electrolyte Membrane (PEM) electrolyzer to convert carbon dioxide to methane, showing that instead of wasting the carbon dioxide in raw biogas, it can be converted to methane using renewable electricity. 

The research is part of SoCalGas' development of technologies known as power-to-gas (P2G), a cutting-edge 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.  

"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," said Yuri Freedman, SoCalGas senior director of business development. "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."

"Southern California has ideal conditions for this type of solution, with significant biogas resources and high penetration of renewable electricity," said Nicholas Flanders, Opus 12's chief executive officer. "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."

Raw biogas is mostly methane, but also contains about 30 to 40 percent carbon dioxide, 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 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. 

Opus 12

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