There are plenty of efforts to make fossil fuels more “green,” or compatible with the environment, but few are gaining the scale of renewable natural gas (RNG), with the number of RNG production facilities more than doubling in the last three years.
Utilities, investors, and consumers are benefiting from the growth of RNG as more methane is being captured and used in heating and transportation applications in the U.S. and Canada, officials in the RNG sector said in recent interviews.
Investment in RNG production facilities has jumped and tracking the environmental attributes has kicked off at the Midwest Renewable Energy Tracking System Inc. The Midwest RETS has enabled many smaller RNG projects move forward in development through placing a value on the renewable attributes, similar to the renewable energy certificates (RECs) market more than 10 years ago, said Ben Gerber, executive director of Midwest RETS.
The cost of RNG production facilities had previously been too high to make sense economically, especially in low-cost energy markets, but the added revenue stream from environmental attributes and tax credits that began in 2014 really boosted the RNG market, added Marcus Gillette, director of public affairs at the Coalition for RNG. The group is seeing announcements of about one project coming online each week, with dozens under construction.
State regulatory and legislative developments have fostered growth in RNG, and while there remain challenges, the fuel has a lot going for it, with positive environmental attributes compared with other fossil fuels, Gillette said.
The production of RNG involves capturing and converting methane from organic waste streams that include landfills, municipal wastewater treatment plants, livestock/poultry manure and commercial food waste through anaerobic digestion facilities. The captured biogas is converted into RNG that can be made compatible with conventional natural gas pipeline and distribution systems to be used by utility customers or compressed as a transportation fuel.
Other efforts to lessen the carbon footprint of fossil fuels include carbon capture, storage, and utilization, reducing methane leaks at production facilities and Norway’s plan to have floating offshore wind turbines provide power to offshore oil and natural gas production facilities. Those are gaining traction, but slower than the RNG developments.
The increased attention on methane emissions have been a positive in growing the RNG market, Gillette said. California led the way through efforts to reduce methane emissions many years ago, and with high agricultural production in the state – which enables more anaerobic digestion – RNG has been a great success story of those efforts, he said.
Not all RNG is created equal, however. The way the biogas is captured and the type of decaying organic material that produces it can make a difference in how much of an environmental benefit it provides, according to the Environmental Defense Fund (EDF).
An EDF blog post by Joe Rudek and Stefan Schwietzke asserted that RNG production only generates climate benefits if it replaces fossil fuel. The post notes that the World Resources Institute listed two conditions to consider when assessing the climate effect of RNG. The first is that the biogas must be produced from waste, and not other sources of organic material, such as purpose-grown crops and timber, as the latter group can result in increased methane concentrations in the atmosphere.
The second condition is that the system of capturing the methane should not result in higher methane emissions. In some cases, a landfill that flares biogas could have less emissions than a capturing system that processes it and moves it through a pipeline network, the EDF authors said.
“Since it’s clear that biogas must be sourced responsibly to be a true climate win and avoid creating more problems than it solves, state and local agencies must be careful not to overestimate the volume of biogas available to replace fossil fuels,” Rudek and Schwietzke said. State regulators and lawmakers “should closely evaluate new biogas proposals to determine if they really can deliver climate benefits,” they wrote.
The Minnesota Public Utilities Commission (PUC) is doing just that after denying a pilot RNG program from CenterPoint Energy Minnesota Gas in late July. The PUC denied the pilot program without prejudice, and CenterPoint is looking toward filing a revised plan to bring an RNG option to utility customers.
The PUC order that was voted on at the July 26 meeting is not available, though it should be soon, a spokesman for the PUC said August 22.
Oregon has followed California’s path on low carbon fuel standards, and although the RNG market there is a fraction of the size of California, environmental credit prices are reaching all-time highs and development of RNG production facilities there is increasing, Gillette said.
Several natural gas utilities have been pioneers in using RNG and extolling its benefits for many years, with Vermont Gas, Southern California Gas Co., Northwest Natural Gas and National Grid in New England among them.
FortisBC in British Columbia Enbridge in Alberta and Ontario and Heritage Gas in Nova Scotia also are pursuing RNG efforts, though the cost of RNG production in today’s low-cost energy market is among the challenges being tackled.
That is where state and provincial laws and regulatory proposals can play a large part in development of RNG. At the National Association of Regulatory Utility Commissioners summer meeting, Emily O’Connell of the American Gas Association referenced 18 states where either voluntary utility programs, legislative plans or applications with PUCs have been filed. Among those 18 states, nine bills have become laws and 13 applications have been filed with PUCs, with other applications approved by state regulators, noted O’Connell, director of energy markets policy at AGA.
The American Gas Foundation is working on a new study that will assess all opportunities to utilize the natural gas pipeline system to deliver RNG to all sectors of the economy. The resource potential assessment will include all technologies available for producing RNG. Those include anaerobic digestion, power-to-gas projects that use electricity from renewable resources to produce natural gas from hydrogen and other gasification projects that convert organic material into RNG.
Dominion Energy and Smithfield Foods Inc. on August 20 announced the latest development in their Align RNG partnership, a multi-state effort where methane emissions from hog farms are captured and converted into RNG for use in the natural gas distribution system. The partnership began in late 2018 and the companies broke ground for construction of North Carolina’s largest RNG project that will aid farmers with additional revenue, reduce greenhouse gas emissions and contribute towards Dominion’s renewable energy efforts. The 300,000 MMBtu of renewable energy from the project will play a key role in North Carolina’s plan to reduce GHG emissions over the next decade, officials said.
Such projects illustrate how not only are state regulatory efforts a factor in RNG development, but corporate initiatives to reduce carbon footprints, said Gerber of Midwest RETS. Large companies have been moving toward 100% renewable energy goals on the power side of their usage for many years, but their thermal use of energy for heating or manufacturing is the next frontier, and many companies are turning to RNG development, he said. Full electrification is not always suitable and RNG allows companies to minimize carbon footprints while continuing to use natural gas piping and infrastructure, Gerber noted.
Of the RNG production sites being developed or announced recently, there is even distribution among landfill projects, wastewater facilities and food waste or agricultural projects, Gillette said. Previously, the low-hanging fruit was at large landfills where municipalities were required to capture or minimize methane emissions, he noted.
Even in New York City, where increased natural gas use has been a challenge, RNG is making headway. Manhattan College on August 15 said it is partnering with the city’s Department of Environmental Protection and others to use the output from anaerobic digestion at municipal wastewater and landfill facilities. The project, which received funding from the New York State Energy Research and Development Authority, includes RNG production from Newtown Creek, the largest of New York City’s 14 wastewater treatment facilities.
On the investment side, private investment firm Newlight Partners LP recently announced funding of $106 million for Bioenergy DevCo, a Maryland-based company that has more than 200 RNG projects around the world. As more cities and companies in the U.S. are looking to reduce waste at crowded landfills and use more renewable energy resources, Bioenergy DevCo’s technology will capitalize on the promise of the RNG market, Newlight officials said in a statement.
“In working with Newlight, we address the strong and increasing demand for our anaerobic digestion technology, which is proven to naturally transform organic waste into clean, renewable natural gas, in a way that meets the unique needs of municipalities and companies around the country,” said Shawn Kreloff, founder and CEO of Bioenergy DevCo.
By Tom Tiernan firstname.lastname@example.org
 For a past story, see, Minnesota PUC Denies CenterPoint Pilot on Renewable Natural Gas, FR No. 3260, pp. 14-16.