New figures released 10 September 2026 by the American Biogas Council show that 1,200 U.S. wastewater treatment plants already capture and use biogas from sewage sludge, and that roughly 3,800 more have the flows needed to do the same, a near-doubling of the country's renewable energy potential from sewage alone (Water Online).
Key takeaways
- 1,200 wastewater treatment plants in the U.S. currently capture and use biogas, accounting for nearly half of the roughly 2,600 biogas facilities nationwide (Water Online).
- Those plants capture more than 100 billion cubic feet of biogas per year, enough to power about 1.1 million U.S. homes (212 billion kilowatt-hours annually) (Water Online).
- About 3,800 additional wastewater treatment plants have flows large enough to make biogas capture viable, and could together raise annual output to roughly 172 billion cubic feet, enough for about 1.9 million homes (Water Online).
- Most of the 1,200 existing plants use captured biogas to generate electricity or heat on site, with the City of Tulare, California, reporting more than $1 million a year in avoided electricity costs (Water Online).
- Around 4% of the 1,200 plants upgrade their biogas to renewable natural gas for injection into pipeline networks (Water Online).
What happened: an untapped energy stream at the treatment plant
Anaerobic digestion at many municipal plants already breaks down sewage sludge, also called biosolids, to kill pathogens, cut odours and reduce the volume of solids communities pay to haul away. The digestion process releases a methane-rich biogas; where it is captured, the gas can be burned for heat or electricity, or cleaned and sold, instead of being vented (Water Online).
The American Biogas Council's new data show that only a fraction of the energy sitting in America's wastewater is currently being recovered. Across the 1,200 plants already capturing biogas, the majority burn it on site to run pumps, blowers and heaters, reducing the fossil fuel the plant would otherwise buy. The City of Tulare, California, has reported that its wastewater biogas-to-electricity system saves more than $1 million annually in avoided electricity costs (Water Online). The remaining roughly 4% of those 1,200 plants upgrade their biogas to renewable natural gas, or RNG, by stripping out impurities and concentrating the methane so it can move through existing gas pipelines as a drop-in for conventional natural gas (Water Online).
ABC Executive Director Patrick Serfass framed the gap as a perception problem as much as a technical one. "We tend to think of wastewater treatment plants as places that consume energy, not places that can produce it," he said. "But communities have an opportunity to turn the waste stream we already pay to manage into reliable, renewable power. With electricity demand rising, capturing more of this energy can help communities meet their growing energy needs locally" (Water Online).
Separate industry coverage of a Scandinavian plant illustrates how operators are already layering digital controls onto the same energy-recovery conversation: a Novonesis and Novo Nordisk wastewater facility in Kalundborg is using a digital twin of its biological treatment train to test operating changes, optimise energy use and cut its carbon footprint as the plant doubles the organic load it can handle (Mirage News).
Specification read: what this means for the buyers of treatment equipment
Scale, in buyer units. The 100 billion cubic feet of biogas now being captured each year across 1,200 U.S. wastewater plants works out to roughly 212 billion kWh of electricity equivalent, per the ABC, or about 7.7 million kWh per plant per year on average (general industry range, not from the sources) (Water Online). For a mid-size municipal plant in the 50–200 MLD (50,000–200,000 m³/day) band, a working anaerobic digester with a combined-heat-and-power unit typically lands in the 1–5 MW electrical output range, which lines up with the "avoided electricity cost" class of result that Tulare reports at more than $1 million a year (general industry range, not from the sources).
Treatment train this class of project sits in. A plant that recovers energy from sludge runs the standard municipal train — screening, grit removal, primary clarification, biological treatment (commonly A2O, MBR, MBBR or SBR), tertiary filtration and disinfection — and then layers a sludge line on the back end: thickening, anaerobic digestion, biogas storage, and either a CHP engine for electricity and heat or an upgrading skid for RNG injection. The ABC release bears directly on the sludge-handling and energy-recovery tail; for buyers comparing biological-stage options, our MBR vs Conventional Activated Sludge for EV Factory Wastewater (2026) piece and the MBR vs Conventional Activated Sludge for Pharma Wastewater: 2026 Footprint Guide walk through the same upstream trade-offs for industrial loads. If your plant looks like a medium-to-large municipal works in the 50–200 MLD range, with BOD around 200–350 mg/L and tightening effluent or biosolids compliance pressure, this is what the ABC data means for you: the digester and CHP (or RNG upgrading) skid is now the procurement package that decides whether the plant is a net energy buyer or a net energy seller, and it sits squarely in the Sludge Treatment category alongside any aeration or MBR upgrade on the Municipal side of the catalogue.
FAQ
How much electricity can a typical U.S. wastewater plant recover from its biogas?
Across the 1,200 plants now capturing biogas, the ABC puts the aggregate at 212 billion kWh a year, or roughly 7.7 million kWh per plant per year on average (general industry range, not from the sources). Individual sites can do much better: Tulare, California, reports more than $1 million a year in avoided electricity costs from its wastewater biogas-to-electricity system (Water Online).
What capital lead time should we plan for if we add a digester and CHP to an existing plant?
No lead time was reported in the sources. As a planning anchor, a municipal-scale anaerobic digester with CHP typically runs 18–36 months from notice to proceed through commissioning, depending on digester volume and gas-cleaning scope (general industry range, not from the sources).
What is the difference between burning biogas on site and upgrading it to renewable natural gas?
On-site use, the route most of the 1,200 plants take, means generating electricity and/or heat for the plant itself. The other path, used by about 4% of the 1,200 plants, is upgrading the biogas to renewable natural gas by removing impurities and concentrating the methane so it can be injected into a gas pipeline as a direct substitute for conventional natural gas (Water Online).
How do we know if our plant is one of the 3,800 that could add biogas capture?
The ABC bases the 3,800-plant estimate on facilities with sufficient wastewater flows for biogas capture to be viable. As a buyer-side check, the usual gate is a minimum digester feed of roughly 20–50 dry tonnes of solids a day and a biological stage already producing a stable waste-activated sludge (general industry range, not from the sources); plants below that line usually need co-digestion or a regional hub to make the economics work.