Sustainability Energy

Turning cow waste into clean power on a national scale

Cows eat near a methane waste digestor that turns manure into energy
Manure from these cows is turned into methane that’s burned for energy. Getty Images

Story at a glance

  • The Dominion Energy, Vanguard Renewables and Dairy Farmers of America project is the first nationwide network of waste-to-energy projects for dairy.
  • Supporters call the project a triple win.
  • Critics worry some methane could escape into the atmosphere.

A 1,000-pound dairy cow produces an average of 80 pounds of manure each day. Multiply that by the estimated 9 million dairy cattle in the U.S., and that’s a lot of manure. 

Dominion Energy, one of the nation’s largest energy producers —  headquartered in Richmond, Va. — wants to put some of that tremendous amount of livestock waste to good use by converting poop into power, while at the same time, reducing pollution. 

Already recently partnered with pork giant Smithfield Foods, Dominion has now launched a second waste-to-energy project in a strategic partnership with Vanguard Renewables and the Dairy Farmers of America.  

Dominion Energy says its partnership with Smithfield is the nation’s largest renewable natural gas (RNG) partnership and that the Vanguard partnership is the first nationwide network of waste-to-energy projects for dairy. “The projects are a powerful example of the environmental progress we can make through innovation and partnering with other industries,” says Ann Nallo, who works in media relations for Dominion Energy. 

By harnessing methane from livestock manure in both projects, the company hopes to simultaneously heat homes and combat climate change. According to Dominion Energy, the hog and dairy projects combined will “generate enough clean energy to heat nearly 100,000 American homes and will substantially reduce greenhouse gas emissions from U.S. farms.” The reduction in greenhouse gas emissions “will be equal to taking 650,000 non-electric vehicles off the road or planting nearly 50 million new trees each year,” says Nallo. 

“The project is a triple win,” she says. “It’s a new source of clean energy for customers, a new source of revenue for family farmers, and there are significant benefits to the environment.” 

Methane is produced from a variety of natural sources — including cow and pig manure. When animal waste and other organic material decomposes, it produces methane. Although methane emissions are lower than carbon dioxide emissions, it is considered a major greenhouse gas because each methane molecule has 25 times the global warming potential of a carbon dioxide molecule, according to the Land Trust Alliance

When asked about Dominion Energy’s new waste-to-energy project, Joshua Lynsen, a Land Trust Alliance spokesperson, said, “While we’re not in a position to comment on this particular project, capturing and destroying methane to prevent its emission into the atmosphere is a good thing for the environment and can help combat climate change.”   

Virginia Department of Environmental Quality Chief Deputy Director Chris Bast tells Changing America, “Capturing methane from hog lagoons and dairy farms and converting it to electricity or renewable fuels is an innovative approach that reduces a potent greenhouse gas and helps protect Virginia waters. We are encouraged by private sector innovation in clean energy and we look forward to continued progress to reduce pollution, protect Virginia’s environment and maintain our high quality of life.”   

How does the process work? Nallo breaks down the waste-to-energy science. Each project consists of a cluster of multiple farms (typically around 15-20), she says. The manure from each farm is stored in covered ponds (called digesters), where bacteria breaks down the manure to generate methane gas. The gas is trapped under the covered lagoon or digester and then transported to a central conditioning facility through underground gathering lines.

“The conditioning facility simply removes the CO2 to make the gas more than 99 percent pure methane, which is indistinguishable from traditional natural gas,” says Nallo. “The conditioning facilities are located along existing distribution lines, so once the gas is processed it can go right into the local distribution system for delivery to homes and businesses.” 

The great thing about RNG, says Nallo, is that it’s “indistinguishable from the natural gas we already use to heat our homes, cook our food and power our businesses.”

When asked if the waste-to-energy project will help the environment, the Sierra Club voiced concerns whether the process is able to capture all the methane. “Even a small amount of consistent methane leakage can be devastating to our climate,” says the Virginia chapter’s Tim Cywinski, citing this and other concerns mentioned in a critical report on the sector from the environmental group Food and Water Watch. In general, Cywinski says, “If Dominion really wants to do right by the climate and communities they serve, they would double down on true clean energy projects — like solar, energy efficiency and wind — and abandon their plans to build fracked-gas plants and pipelines.”

In response to the Sierra Club’s concerns, Kevin Chase, Chief Investment Officer, Vanguard Renewables and CEO, Vanguard Renewables Ag, provided this statement about the Vanguard digesters:

“Anaerobic digesters provide a proven method to capture methane, sustainably process organics, provide financial diversification to the American farmer, and provide green energy to colleges, universities, corporations, utilities, and multinational energy companies. Today climate change is top of mind globally and renewable natural gas is a significant tool to combat this growing challenge. There are many different technologies and approaches for anaerobic digestion and the design is a key determinant of the efficiency of the methane capture. Vanguard has been successfully developing, owning, and operating digesters since 2014, and we are unaware of any commercially deployed manure management system that is more efficient at sequestering methane. We simply do not agree with the Sierra Club’s assessment of the technology’s potential. It does not match our experience.”

In Deerfield, Mass., dairy farmers like Peter Melnik’s family, whose Bar-Way Farm just celebrated its 100th anniversary, have been partnering with Vanguard Renewables to transform cow manure into electricity. “As a businessman, I have to look for ways to strengthen my operation,” Melnik says. “It’s a part of saving our farm, making it more economically viable.” Melnik says the system at his farm captures all the methane. “I don’t want the methane to escape. That’s lost income for me,” he says. In addition, Melnik emphasizes that helping the environment is also a priority by “responsibly handling the waste.”

 In Virginia, Nallo says, “Dominion Energy is taking a comprehensive approach to clean energy and greenhouse gas reduction, and our waste-to-energy (RNG) projects are an important piece.” She adds, “We’re shifting from coal to cleaner natural gas and rapidly expanding renewables to lower carbon emissions from our electric fleet. And we’re also partnering with other industries like transportation and agriculture to help lower their emissions as well.”