SoCalGas’ biomethanation reactor system to be used in Maine

By Southern California Gas Co. | October 19, 2021

SoCalGas’ biomethanation reactor system will be used to help produce renewable energy as part of a power-to-gas demonstration. This system will be installed at an anaerobic digester facility in Clinton, Maine in early 2023.  The power-to-gas process converts renewable electricity into hydrogen.  The biomethanation reactor converts the hydrogen and biogenic carbon dioxide into methane that can be used onsite or injected into the natural gas grid.  

The process will source naturally occurring organic waste from 6 dairy farms in Clinton and other areas in Maine to create biogas which can be used for heating, cooking, and other processes. 

SoCalGas, Plug Power, Electrochaea, and the U.S. Department of Energy’s National Renewable Energy Laboratory worked together to develop the reactor in Golden, Colorado. The biomethanation reactor will be transferred from Colorado to Maine as a key component of this Department of Energy (DOE)-funded project. Summit Natural Gas of Maine was recently awarded nearly $5 million from the DOE to demonstrate power-to-gas with biomethanation process at a dairy digester in Clinton. 

“The development of the biomethanation reactor was a collaborative effort and the technology will help us reach our net zero greenhouse gas emissions target,” said Neil Navin, vice president of clean energy innovations for SoCalGas. Navin continued, “The reactor being utilized across the country shows its effectiveness at a significant scale. Working with other organizations in creating innovative technologies is part of the climate solution.”  

President and CEO of Summit Utilities Kurt Adams said, “With this grant from the Department of Energy, we will develop the first field deployed power-to-gas system in the United States by combining green hydrogen and captured carbon. This will create a carbon negative energy source that can be used to keep homes warm and industries running while reducing emissions.”

SoCalGas devised the initial project with its partners and funded the construction to prove the technology could work on a pilot scale.

NREL’s Senior Research Scientist Nancy Dowe said, “SoCalGas has been a pioneer in developing the biomethanation process with NREL and Electrochaea where self-replicating single-celled organisms transform carbon dioxide and hydrogen into renewable methane.”

Dowe continued, “SoCalGas funded the design, fabrication and validation of the bioreactor system at NREL that was successfully commissioned in 2019. Now, with this new project at a diary digester, we feel like we are graduating to a real biogas source and enabling impactful research in the field at a meaningful scale.”

Ole Hoefelmann Plug Power’s general manager electrolyzer solutions said, “At Plug Power we are excited to be part of this power-to-gas project.  Solutions, such as the one being developed here, that reuse captured CO2 by combining it with Green Hydrogen, produced from renewable energy resources, allows industries to have a positive impact on the environment while being able to use existing assets during the energy transition.”

The newly created “green” hydrogen is combined with carbon dioxide and piped into the reactor where archaea microorganisms produce renewable natural gas by consuming hydrogen and carbon dioxide and emitting methane. 

The system is capable of recycling carbon dioxide from a myriad of sources, such as ethanol plants and anaerobic digesters, preventing greenhouse gas emissions and displacing the consumption of fossil methane.  

"Expanding our collaboration with SoCalGas and NREL to include Summit Utilities provides the opportunity to use our biomethanation technology at a dairy biogas project.  When biogas is fed into the biomethanation reactor, CO2 release is avoided and the amount of renewable methane produced from dairy waste is nearly doubled.  Summit's deployment of the Electrochaea technology will lead the way to greening of the gas grid and long-term storage of renewable energy in the methane molecule," added Doris Hafenbradl, chief technology officer of Electrochaea. 

Summit’s digester project is among 22 selected projects focused on producing cost-effective, low-carbon biofuels that are receiving funding from the DOE. 

Adams said, “We are grateful for the support from the Department of Energy, our congressional delegation, and our many partners on this project including SoCal Gas, National Renewable Energy Laboratory, Plug Power, and Electrochaea.” 

Project operations are expected to begin at the end of 2023.