New Data Shows Wastewater Facilities Produce 7.3 Billion kWh of Energy Each Year — With Greater Potential Available

(American Biogas Council) As electricity demand soars, biogas made from wastewater sludge offers an established power source -- Today (September 25, 2025), the American Biogas Council (ABC) released new data showing the extensive role municipal wastewater facilities can play to recycle organic waste into renewable energy and fertilizer using biogas systems. Today, more than 1,200 U.S. wastewater treatment plants capture biogas from their wastewater sludge and use it to produce the electricity equivalent of 7.3 billion kWh per year. The data also show significant untapped potential: About 3,800 additional wastewater facilities – over three times as many – could build biogas capture systems but have not. If every suitable wastewater facility installed biogas systems, the sector could capture 171.8 billion cubic feet of biogas each year – enough energy for 1.3 million U.S. households.

The ABC’s research provides the first comprehensive survey of U.S. biogas capture systems at wastewater plants in more than a decade. The analysis draws on data collected from more than 5,000 wastewater plants that treat at least a million gallons of wastewater a day (1 MGD).

“Biogas systems have the potential to unlock an unprecedented supply of U.S.-made energy, and wastewater facilities can help make that happen” said the ABC’s Executive Director Patrick Serfass. “Investing in biogas capture at wastewater facilities creates a win-win scenario. Waste is recycled instead of discarded, and the U.S. can tap enough new energy to power the homes of millions of Americans across the country.”

Wastewater biogas facilities convert their sludge, or biosolids, using anaerobic digestion systems, which capture biogas produced as the waste breaks down. Even though wastewater plants frequently use their biogas to generate power on-site and put only excess electricity onto the grid, they significantly ease electricity demand, which is soaring from data centers and an increase in domestic manufacturing. (Biogas systems also capture energy from waste at landfills, on farms, and at dedicated food waste biogas facilities.)

The wastewater industry pioneered the use of biogas systems in the U.S. beginning in the 1920s, at first simply to reduce the volume of sludge they needed to manage from wastewater treatment (digesting the sludge cuts its volume by about 50%). In the decades that followed more and more facilities have added anaerobic digesters, increasingly to provide biogas to generate electricity or heat for plant operations. ABC’s new research shows that the industry added roughly 100 biogas facilities per decade at wastewater facilities from 1960 to 1990.

Today, 49% of all biogas capture systems in the U.S. operate at wastewater plants, followed by farms (24%) and landfills (23%). Because wastewater biogas capture systems are typically smaller than other types of biogas facilities, they produce only 12.5% of total U.S. biogas output despite their relative prevalence. However, digesting local food waste with sludge at wastewater plants offers wastewater facilities a powerful opportunity to enhance biogas output while recycling organic waste into energy.

The data also detail how plants use captured gas: 80% generate energy, with 58% producing electricity and 22% producing heat. Only 4% of wastewater plants upgrade raw biogas to renewable natural gas (RNG), a lower proportion than in other biogas sectors.