Construction has begun on a 13.4-MW advanced technology biogas cogeneration plant for the Sacramento Area Sewer District (SacSewer).
SacSewer is the largest sewage collection, treatment and resource recovery utility in the Sacramento, California, area and the second largest in the state. The utility serves more than 1.6 million people.
The renewable energy facility is being built near Elk Grove, California, at the EchoWater Resource Recovery Facility, one of the largest water resource recovery facilities in the U.S.
Powered by waste: The circular economy in action
Water and wastewater utilities are increasingly turning to renewable energy resources, including microgrids, to reduce costs and emissions and protect public health and safety.
In this case, the cogeneration plant will use methane, a biogas byproduct of the solids treatment process conducted at EchoWater, to generate renewable electricity and heat.
The plant will offset some of the power and thermal energy required by the wastewater treatment facility, which will remain connected to the grid.
Fuel cell technology will also be employed to store excess electricity, reduce emissions and ensure the cogeneration plant is a reliable and dispatchable energy resource. The fuel cells could also be used in the production of hydrogen in the future.
“SacSewer is committed to being a leader in environmental stewardship. Through our sustainable efforts in resource recovery, we maximize the reuse of treatment process byproducts such as biogas,” said Christoph Dobson, SacSewer’s general manager. “This project is yet another example of how we’re working every day to fulfill our mission of protecting public health and the environment by collecting, treating and recovering resources from sewage.”
Combusted methane does produce some greenhouse gas (GHG) emissions such as carbon dioxide (CO2). But pure methane leaked into the atmosphere is calculated to be at least 30 times worse than CO2 as a GHG, according to environmental scientists.
Ameresco awarded project contract
Cleantech integrator Ameresco will develop and build the cogeneration plant under a $140 million contract with SacSewer.
“Capturing and repurposing biogenic methane that is already in our environment and produced by society to displace fossil fuel is a powerful example of the circular economy in action, where waste is not discarded but turned into a valuable asset,” said Michael Bakas, executive vice president of Ameresco.
Construction of the SacSewer renewable energy facility is expected to be complete by July 2026.
