California researchers looks to convert carbon dioxide to renewable natural gas

Lawrence Livermore National Laboratory (LLNL), in collaboration with Southern California Gas Co. and Stanford University, has developed a process to convert carbon dioxide to renewable natural gas using microbes.

This process of converting carbon dioxide to methane using renewable electricity is known as microbial electromethanogenesis (ME). ME allows for the storage of excess renewable electricity, which increases renewable natural gas availability, lowers the cost of producing renewable natural gas, and decreases carbon dioxide emissions.

The project is funded in part by an $800,000 grant from the U.S. Department of Energy. Southern California Gas will also provide $400,000 in funding, on top $125,000 of seed funding it provided in 2017.

“Through this project we intend to devise scalable, efficient prototype reactors that enable both economical upgrading of biogas and storage of renewable electricity as methane,” LLNL chemist Sarah Baker said. “To do this, we will leverage recent advances in materials synthesis and manufacturing to fabricate reactors tailored to the requirements of the microbes and the overall process.”

Stanford’s Spormann Laboratory has done past research on microbes that create methane, while LLNL has made advances in 3D printed carbon aerogel electrode materials.

The development of this process – called power-to-gas – has advantages over storing renewable energy in batteries. One, unlimited amounts of electricity can be easily stored for very long periods of time, and two, it can be stored and used with existing infrastructure.

“This technology has the potential to cut the cost of processing biogas to make pipeline-quality renewable natural gas while producing nearly twice the amount of this easily stored renewable energy and reducing carbon dioxide emissions,” Yuri Freedman, Southern California Gas senior director of business development, said. “It could make a big difference for small-scale biogas producers like dairy farms and feedlots, which collectively make up the majority of California’s renewable natural gas potential.”

If excess solar and wind energy were converted to methane and stored as renewable natural gas, it would provide enough energy for Califronians. Natural gas could be provided for around 2.4 million California homes with renewable natural gas derived from the state’s existing organic waste, according to the University of California, Davis.

The research is expected to be complete by late 2020.