Landfills as an economic resource

Rachel Goldstein, Program Manager, Landfill Methane Outreach Program, U.S. Environmental Protection Agency, Washington, D.C.; Chad Leatherwood, P.E., Senior Project Professional, SCS Engineers, Asheville, North Carolina, and Presenter, 2007 APWA Congress

Most people do not think of landfills as much more than a necessary evil at best, a community liability at worst. However, society's current primary method of waste management produces a by-product with a significant energy value, landfill gas (LFG).

A landfill can provide a valuable, lower-cost supply of energy that also is considered green in many places. Additionally, the collection and control of LFG results in significant reductions in greenhouse gas (GHG) emissions. With the greater focus on climate change, a burgeoning market for GHG emission offsets is emerging and landfills are posed to bring these GHG offsets to market, resulting in an additional income stream to landfill owners. Local governments are increasingly recognizing landfill gas for its many benefits. This article will cover how local governments can use landfill gas as an economic resource.

Background
Landfill gas is the natural by-product of the decomposition of organic waste in landfills and is comprised primarily of methane, the main component of natural gas, and carbon dioxide. Instead of allowing LFG to escape into the air, it can be captured, converted and used as an energy source. Using LFG has multiple benefits such as reducing odors and other hazards associated with LFG emissions, and preventing methane from migrating into the atmosphere and contributing to local smog and global climate change. Methane is a potent greenhouse gas, about 21 times more so than carbon dioxide.

  A landfill gas pipeline feeding a boiler

Landfill gas is extracted from landfills using a series of wells and a blower/flare (or vacuum) system. This system directs the collected gas to a central point where it can be processed and treated depending upon the ultimate use for the gas. From this point, the gas simply can be flared or used to generate electricity, replace fossil fuels in industrial and manufacturing operations, fuel greenhouse operations, or be upgraded to pipeline quality gas.

EPA's Landfill Methane Outreach Program (LMOP) has seen a dramatic increase in projects over the past ten years. Currently 424 projects are online in the U.S. alone and over 1,100 worldwide. While this number is impressive, the industry still has a long way to go. According to the EPA LMOP, at least 560 landfills exist that could economically support a project. These landfills would have a generation capacity of over 1300 MW or could supply 250 billion cubic feet per year of gas to industrial end users.

The generation of electricity from LFG makes up about two-thirds of the current operational projects in the U.S. Electricity for onsite use or sale to the grid can be generated using a variety of different technologies, including internal combustion engines, turbines, microturbines, Stirling engines (external combustion engine), and Organic Rankine Cycle engines. The vast majority of projects use internal combustion engines or turbines, with microturbine technology being used at smaller landfills and in niche applications. Some electrical generation projects increase overall efficiency by using waste heat from the generating device to provide hot water or steam for another use.

Direct use of LFG to offset the use of another fossil fuel is occurring in about one-third of the current operational projects. This direct use of LFG can be in a boiler, dryer, kiln, greenhouse, or other thermal applications. Furthermore, a trend in community-inspired smaller LFG projects is emerging that provide low-cost fuel for uses such as pottery kilns, glass furnaces, blacksmithing, greenhouses and biodiesel production.

In several cases, local governments are using LFG to cut operating costs and minimize environmental impacts. Project types currently in operation that show the versatility of LFG uses include:

  • Boiler fuel providing steam for correctional facilities, hospitals and schools
  • Wastewater treatment plant sludge drying operations
  • Infrared heaters for maintenance facilities
  • Electrical generation and cogeneration projects

Market Drivers for LFG Utilization
In the past few years, LMOP has seen increasing interest in utilizing LFG, particularly for direct use. The interest is fueled by economic and environmental factors. Energy costs have increased significantly over the past decade, show greater volatility, and are subject to extraneous activities, such as hurricanes, that are outside the control of fuel consumers. Higher prices not only encourage energy users to look for less expensive sources, but they make project economics more attractive. Industries of all types seek to become more competitive by reducing fuel costs, and communities have been able to attract new businesses by marketing LFG as a low-cost energy resource.

Local governments are realizing significant savings on their energy costs when they use LFG in addition to providing a mechanism for meeting environmental goals. The Antioch Community High School in Illinois notes that it saves over $100,000 per year in energy costs through the use of LFG to generate electricity and capture waste heat from the microturbines. Fairfax County, Va., notes savings of almost $6,000 per year by using of 30 cubic feet per minute of LFG in infrared heaters at a maintenance facility, significant savings from a small amount of LFG. The City of Denton, Tex., uses LFG to produce biodiesel for its diesel fleet, resulting in 12 tons per year reduction in criteria pollutants.

LFGE projects have been instrumental in creating jobs and commerce in economically stagnant areas. Average-sized LFG projects can increase regional employment by approximately twenty full-time jobs during the construction phase and by two to six jobs during the operational phase. This is in addition to significant increases in local economic output and tax revenue.

The economic benefits are certainly a powerful motivator but environmental stewardship and corporate social responsibility also are strong market drivers for landfill gas projects. Good corporate citizens are joining voluntary programs for GHG reductions. This demand for GHG reductions has resulted in another economic benefit for landfill owners. Voluntary collection and control of LFG provides such GHG offsets. According to the Chicago Climate Exchange, GHG offsets currently are trading for over $3.00 per ton of CO2. Given that the destruction of one ton of methane equals 18.25 tons of CO2, reduction in such projects can provide additional income streams to landfill owners.

Is a Landfill Gas to Energy Project in Your Future?
Are you interested in using LFG as an energy source? Do not know where to start? LMOP has a number of tools that can help determine if a landfill gas energy project is in your future. LMOP offers technical support that includes finding a landfill, estimating gas generation, evaluating project possibilities, identifying applicable project incentives, and conducting project economic analysis (see www.epa.gov/lmop for more information).

Using LFG for energy is a win/win opportunity. Landfill gas energy projects involve citizens, nonprofit organizations, local governments, and industry in sustainable community planning and creative partnerships. These projects go hand-in-hand with community and corporate commitments to cleaner air, renewable energy, economic development, improved public welfare and safety, and reductions in greenhouse (global warming) gases. By linking communities with innovative ways to deal with their LFG, LMOP contributes to the creation of livable communities that enjoy increased environmental protection, better waste management, and responsible community planning.

Chad Leatherwood will give a presentation on this topic at the 2007 APWA Congress in San Antonio. His session is entitled "Landfills That Clear the Air?" and takes place on Monday, September 10, at 3:00 p.m. He can be reached at (828) 285-8951 or cleatherwood@scsengineers.com. Rachel Goldstein can be reached at (202) 343-9391 or goldstein.rachel@epamail.epa.gov.