America's wastewater treatment plants are capturing only a fraction of their renewable energy potential, according to new figures from the American Biogas Council, which estimates the sector could generate enough electricity for 1.9 million US households a year if biogas capture were rolled out more widely.
There are currently around 2,580 operating biogas capture facilities across the US, with wastewater treatment plants accounting for close to half of them. Of the roughly 793 billion cubic feet of biogas captured annually across all sectors, wastewater contributes about 100 billion cubic feet, or 12.5 per cent of the total.
More than 1,200 wastewater treatment plants currently capture biogas, producing just over 100 billion cubic feet a year between them. That is enough to generate around 212 billion kilowatt-hours of electricity annually, sufficient to power approximately 1.1 million US homes today.
The council estimates a further 3,800 wastewater treatment plants have sufficient flow to make biogas capture viable but have yet to install the systems to do so. Bringing these facilities online could lift annual biogas production to around 172 billion cubic feet, enough to supply electricity to approximately 1.9 million homes.
Only about a quarter of the roughly 5,000 US wastewater plants processing more than one million gallons a day have incorporated biogas systems, leaving considerable headroom for expansion. The American Biogas Council is due to publish a nationwide survey of these larger plants in late September 2026.
Among wastewater facilities that do capture biogas, more than 80 per cent use the gas for on-site energy production. Electricity generation and cogeneration is the leading end use, accounting for 69 per cent of biogas captured, while heat-only applications make up a further 12 per cent. Just 4 per cent of wastewater treatment plants upgrade their biogas to renewable natural gas, but because these tend to be larger facilities, they account for 13 per cent of all biogas captured across the sector. A small remaining share is flared or vented rather than put to beneficial use.
By sector, wastewater treatment plants account for 47 per cent of the roughly 2,580 US biogas capture facilities in operation as of August 2026, ahead of agriculture at 24 per cent, landfill at 23 per cent and food waste at 6 per cent.
Beyond energy generation, the American Biogas Council points to several additional benefits from biogas capture at wastewater plants. Sludge digestion reduces the volume of material requiring handling and disposal by about 50 per cent, and the digested material can be used as a soil fertiliser. Capturing biogas also prevents methane from reaching the atmosphere, putting a potent greenhouse gas to productive use instead. The council notes that older facilities currently flaring their biogas represent a particular opportunity for additional energy recovery and emissions capture.
