Energy & Environment

Methane from Landfills

Methane is one of the most potent greenhouse gases: It's 20 to 25 times more powerful in trapping heat in the atmosphere than carbon dioxide. Although there...
by | August 31, 2009

Methane is one of the most potent greenhouse gases: It's 20 to 25 times more powerful in trapping heat in the atmosphere than carbon dioxide. Although there is debate about whether methane should fall under climate-change regulation or not, nobody doubts that local governments are a leading source of the gas: Landfills are responsible for about one-third of all methane emissions in the United States.

Not long ago, there wasn't much a landfill could do with methane, except burn it. That cuts down the pungent smell and makes nice with neighbors who are unfortunate enough to live near a landfill. Recently, however, localities have come to see methane not just as a stinky nuisance but also as a valuable commodity. Hundreds of landfills around the country have begun transforming methane into electricity and biofuels. The gas can be sent directly to buildings to run heating and cooling systems, can be purified into natural gas, and liquefied or compressed to power garbage trucks and city buses.

"Methane can be used for multiple purposes," says Bruce J. Parker, president and CEO of the National Solid Wastes Management Association. What's more, Parker says, it's reliable. "Unlike sun and solar power, you have continuous access. A landfill is taking gas out 24/7."

Now, efforts to control methane emissions can be monetized, too. Local governments are earning carbon credits for reducing methane emissions, and turning that into cash in emerging markets for trading those credits. For example, the Development Authority of the North Country, a government agency that owns and operates a landfill used by three New York State counties, has begun piping methane out from the garbage heap. It then sends the gas to another facility where it's prepared for use as a heating fuel and used to power a small electric plant. To help pay the operating costs associated with this landfill-gas-to-energy system, DANC has begun selling more than 88,000 carbon credits received through the Climate Action Reserve.

Another landfill that has joined the growing list of facilities earning and selling carbon credits is the 240-acre site owned by the city of Denton, Texas. Last year, Denton also installed a methane capture system and power plant. Vance Kemler, general manager of the city's solid waste services, says the motivation was to reduce pollution while providing the city with some extra money through the sale of these credits. Kemler says landfill-gas-to-energy projects are a "good opportunity for municipalities that own their own landfills to have a positive impact on climate change--and have a new revenue stream."

As a greenhouse gas, methane differs from carbon dioxide in an important way, besides its potency. Methane remains a climate-change threat for a relatively short period of time. Whereas CO2 lingers in the atmosphere for anywhere from 50 to 200 years, methane's lifespan is only nine to 15 years. This makes scientists optimistic that major reductions in methane emissions could lead to a slowing of short-term climate change.

But current regulations regarding landfill gas were crafted in response to odors and pollutants, rather than methane's role in climate change. Under the federal Clean Air Act, only the nation's largest landfills are required to capture methane or burn it off. As technologies for converting methane into energy became profitable, private companies began buying up large municipal landfills to put it to use.

Smaller municipal landfills don't fall under the federal rules. And the cost of capturing and using methane for energy on their own can be too great for some of the smallest local governments to bear. There is some help for these landfills through the U.S. EPA's Landfill Methane Outreach Program, which works with them to determine the economic feasibility of gas-to-energy projects and helps find sources of financing. But it doesn't provide direct financial incentives to landfills that move forward with these projects.

That's where emerging greenhouse-gas emissions markets have become important. One that a growing number of localities are using is based on the Climate Action Reserve. Formed in 2001 by the California legislature, CAR is an independent nonprofit that develops standards for carbon offsets and tracks those offsets. CAR also registers this information so that it can be used as a baseline against which emissions reductions can be measured. Members of CAR whose reductions can be independently verified are given carbon credits, or "offsets," which they can sell via brokers to other organizations. Because methane is so potent as a greenhouse gas, reducing one ton of methane emissions earns as many credits as reducing 20 tons of CO2.

A growing number of private companies are working with municipal landfills to tap these offsets as revenue source. For example, an outfit called Blue Source will pay the upfront costs of a municipal landfill-gas-to-energy project, in exchange for a piece of the profit from offsets trading. "It doesn't take much of a reduction in methane to bring in $100,000 a year," says Annika Colston, Blue Source's vice president of emissions-reduction projects.

Even though the DANC landfill wasn't required under federal law to capture methane, it nevertheless installed a network of vertical wells and pipes to do so in 2001. At first, the methane was simply flared, in order to control the smell. Later, as methane management became a significant cost, officials began looking for ways to tap into new carbon-credit markets to help cover the facility's growing operating costs.

In 2008, after participating in the Chicago Climate Exchange and a few other overseas offset markets, DANC became the first landfill outside of California to be registered on the Climate Action Reserve. As part of the registration process, the landfill worked with New York-based Innovative Energy Systems to construct its three-engine gas-to-energy plant. "To build a power plant of that size is in excess of $10 million," says Bill Seifried, the landfill's general manager. "They built that on their own nickel." DANC and the energy company share revenue generated from the sale of the power plant's electricity.

After a rigorous verification process certifying the landfill's emissions reductions, DANC received its first set of carbon credits in January. The landfill has been able to sell credits retroactively, going back to when its capture program began. DANC has even started to sell some of its credits on an offsets futures market. The success of its landfill-gas-to-energy plant has officials thinking about installing a fourth engine. "Our goal," Seifried says, "is to beneficially use every bit of that gas that we can."

NOTE: This online version corrects the name of the Climate Action Reserve as well as the description of the organization's activities that that appeared in the print version of this article.

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