Ameresco Inc. is the prime contractor on a nearly $140 million new advanced technology biogas cogeneration plant for the Sacramento Area Sewer District at its EchoWater Resource Recovery Facility near Elk Grove.
When it opens in July 2026, the new on-site plant will process methane generated by the sewer district to produce 13.4 megawatts of electricity annually at a cogeneration plant, offsetting the need for the sewer district to buy electricity.
“It is a great renewable project,” said Michael Bakas, executive vice president of Framingham, Massachusetts-based Ameresco (NYSE: AMRC). Methane is produced at the plant “whether we use it or not.”
Part of the processing of wastewater and sewage generates biogas as a byproduct, and of that biogas, about 60% is methane, he said. EchoWater takes the methane, which is a potent greenhouse gas, and feeds it to a fuel cell engine that converts it to energy without combusting it. The main byproduct of that process is hot water, which the plant can use in its processing of sewage, Bakas said.
Typically, Ameresco develops, owns and operates clean energy plants. In this case, it will develop and commission the plant, and SacSewer will own it.
“SacSewer is committed to being a leader in environmental stewardship. Through our sustainable efforts in resource recovery, we maximize the reuse of treatment process by-products such as biogas,” said SacSewer General Manager Christoph Dobson, in a news release. “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."
The Sacramento Regional County Sanitation District and Sacramento Area Sewer District merged into one entity, called the Sacramento Area Sewer District, effective Jan. 1. SacSewer is the second-largest sewage collection utility in California.
All of the sewage treatment for the region of 1.6 million people is handled at SacSewer's EchoWater plant near Elk Grove. The sewer district collects sewage on a regional basis from other districts.
Ameresco has been building plants for 24 years.
The EchoWater plant will use fuel cell technology from FuelCell Energy Inc. (Nasdaq: FCEL), headquartered in Danbury, Connecticut.
“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,” Bakas said.
The EchoWater plant can be expanded to produce hydrogen in the future.
