EPA issues 2 proposals to reduce landfill gas emissions

By Erin Voegele | August 17, 2015

On Aug. 14, the U.S. EPA issued two proposals to further reduce emissions of methane-rich gas from municipal solid waste (MSW) landfills. Under the proposals, new, modified and existing landfills would begin collecting and controlling landfill gas at emission levels nearly a third lower than current requirements.

According to the EPA, MSW landfills are the third-largest source of human-related methane in the U.S., accounting for 18 percent of methane emissions in 2013—the equivalent of approximately 100 million metric tons of carbon dioxide pollution. Combined, the proposed rules are expected to reduce methane by an estimated 487,000 tons per year beginning in 2025. This is the equivalent to reducing 12.2 million metric tons of carbon dioxide.

The two proposals released on Aug. 14 strengthen a previously proposed rule for new landfills that was issued in mid-2014, and would update the agency’s 1996 emission guidelines for existing landfills. According to the EPA, the new proposals are based on additional data and analysis and public comments received on the proposal and advance notice of proposed rulemaking issued last year. Both proposals are part of the Obama administration’s Climate Action Plan—Strategy to Reduce Methane Emissions, which was first announced in March 2014. 

Regarding the EPA’s proposed emission guidelines for existing landfills, approximately 989 open and closed landfills are expected to be subject to the proposed emission guidelines. Of these, 574 are currently required to collect and control their emissions. According to information published by the EPA, the agency is proposing to update the emissions threshold that triggers a requirement to install landfill gas collection control systems. The current threshold is set at 50 metric tons per year or nonmethane organic compounds. Under the proposed rule, the threshold would be lowered to 34 metric tons for active landfills. Closed landfills would remain subject to the current threshold of 50 metric tons per year. The proposed updates would apply to landfills that began construction, reconstruction or modification on or before July 17, 2014, and accepted waste after Nov. 8, 1987.

Under the proposal, an additional 106 open landfills are expected to be required to collect and control landfill gas emission, bringing the total number of open and closed landfills collecting and controlling emissions to 680 in 2025. The EPA has also predicted an additional 105 open landfills would have to report their emissions, but would not be required to collect them.

According to the EPA, the proposed emission guidelines would retain a number of current requirements, including a requirement that existing landfills be subject to the guidelines if they have a design capacity of 2.5 million metric tons and 2.5 million cubic meters of waste. In addition, the EPA has indicated that a well-designed and well-operated landfill gas collection and control system would be the best system of emission reductions for controlling landfill gas. The agency noted landfill gas owners/operators may control gas by putting it to beneficial use by combusting it in an enclosed combustion device for energy production, by using a treatment system that processes the collected gas for sale, or by flaring it.

EPA estimates the value of the climate-related benefits of the proposed rule will be $670 million in 2025, which is more than $14 in benefits for every $1 spent to comply. The nationwide cost for complying with the proposed guidelines is an estimated $47 million per year in 2025. This includes the cost of installing and operating a gas collection and control system. At some landfills, it also includes the cost of an engine that uses the landfill gas to generate electricity. According to the EPA, the costs also reflect the revenues landfills may make by selling electricity generated using landfill gas.

Regarding the supplemental proposal for new landfills, the EPA noted the new source performance standards (NSPS) supplemental proposal would change the emissions threshold at which new, modified or reconstructed landfills would be required to begin capturing emissions of landfill gas. In its 2014 proposed rule, the EPA proposed to set the threshold at 40 metric tons per year. The new supplemental proposal would lower that threshold to 34 metric tons per year.

The proposed changes would apply to landfills constructed, modified or reconstructed after July 17, 2014. The EPA estimates 140 landfills would be covered by the NSPS over time. The agency also specified that under the 34 metric ton threshold, 127 new modified or reconstructed landfills would have to begin controlling landfill emissions by 2025, with the remaining 13 required to report their emissions.

According to the EPA, the supplemental NSPS proposal is expected to reduce annual methane emissions by 51,400 metric tons per year beginning in 2025, compared to current requirements—the equivalent of reducing 1.3 million metric tons of carbon dioxide emissions per year. Emissions of nonmethane organic compounds would be reduced by 300 metric tons per year.

The agency estimates the value of climate-related benefits in the supplemental proposal will be $78 million in 2025, which equates to more than $9 in benefits for every $1 spent to comply. The nationwide cost of complying with the supplemental proposal is an estimated $8.5 million per year in 2025. This includes the cost of installing and operating a gas collection control system, and at some landfills, the cost of an engine to convert the landfill gas into electricity. The costs also reflect the revenues landfills may make by selling electricity generated with landfill gas.

The EPA will open a 60-day public comment on each proposal following publication in the Federal Register. Prepublication versions of the proposed updates to emission guidelines and the NSPS supplemental proposal can be downloaded from the EPA website