Could Renewable Natural Gas Be the Next Big Thing in Green Energy?
In Europe and the U.S., the growth of this renewable methane gas is growing as businesses capture large amounts of methane from manure and food wastes from landfills, farms, and sewage plants. This positive trend could be another large step in the ending the fossil fuel industry.
In the next few weeks, construction crews will begin building an anaerobic digester on the Goodrich Family Farm in western Vermont that will transform cow manure and locally sourced food waste into renewable natural gas (RNG), to be sent via pipeline to nearby Middlebury College and other customers willing to pay a premium for low-carbon energy.
For the developer, Vanguard Renewables, the project represents both a departure and a strategic bet. The firm already owns and operates five farm-based biogas systems in Massachusetts; each generates electricity on site that is sent to the grid and sold under the state’s net-metering law. The Vermont project, however, is Vanguard’s first foray into producing RNG — biogas that is refined, injected into natural gas pipelines as nearly pure methane, and then burned to make electricity, heat homes, or fuel vehicles.
Biogas has been around for a long time in the United States, mainly in the form of rudimentary systems that either capture methane from landfills and sewage treatment plants and use it to produce small amounts of electricity, or aging digesters at dairy operations that might power a local farm and send some surplus power to the grid. But those are fast becoming outdated and out-produced by a new wave of large-scale renewable natural gas projects that are springing up around the country. These ventures are tapping into heretofore unexploited sources of energy: some are capturing the vast amounts of methane generated by manure from some of the 2,300 hog farms that dot eastern North Carolina; some are building biodigesters to turn clusters of large California dairy farms into energy hubs; and some are seeking to divert food waste from landfills and transform it into vehicle and heating fuels.
Renewable natural gas is reaching a tipping point for several reasons: An increasing number of third-party operators like Vanguard are relieving farmers and landfills of the burden of running their own energy systems and are introducing more sophisticated technologies to capture methane and pump it directly into pipelines. Some states, including California, are passing laws requiring the development of renewable natural gas. And utilities across the country are starting to support these new initiatives, as evidenced by the new partnership between Dominion Energy and Smithfield Farms — the world’s largest pork producer — to develop new hog waste biogas projects. For proponents, the ultimate goal is to replace a significant portion of the fossil-derived natural gas streaming through U.S. pipelines with pure methane generated by human garbage and animal and agricultural waste.
The untapped potential — especially of the billions of gallons of animal manure and millions of tons of food waste generated each year in the U.S. — is immense. According to a 2014 “Biogas Opportunities Roadmap” reportproduced by the U.S. Environmental Protection Agency, the Department of Agriculture, and the Department of Energy, the U.S. could support at least 13,000 biogas facilities, fed by manure, landfill gas, and biosolids from sewage treatment plants. Those new systems could produce 654 billion cubic feet of biogas per year — enough renewable energy to power 3 million homes. And a study by the World Resources Institute estimated that the 50 million tons of organic waste sent to landfills or incinerated every year in the U.S has the energy content of 6 billion gallons of diesel fuel, 15 percent of all diesel consumed by heavy-duty trucks and buses.
The former manager of the EPA’s anaerobic digestion programs, Chris Voell, was so impressed with Denmark’s biogas operations — which are highly engineered to digest a mix of household food scraps, residuals from food processing businesses, and livestock manure — that he now works for the Danish Trade Council to introduce Danish digester technology and business models to the U.S market.
Market forces alone, however, won’t be enough to usher in a biogas revolution. The single policy that could supercharge the growth of biogas and RNG in the U.S., most industry observers and insiders agree, is a federally legislated price on carbon. But given that a carbon tax or comprehensive climate bill aren’t likely to emerge any time soon under the current administration, Hanselman says the next best thing the federal government could do is reinstate the investment tax credit for digester systems, which lapsed in 2016.
Despite these challenges, Voell thinks there is now enough momentum to see biogas finally gain widespread traction as a renewable energy source in the U.S.
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