Despite mounting concerns over dependable and sustainable fuel supplies, the idea of converting landfill gas to energy still faces challenges from friends, foes, and a vast majority of the public who haven't a clue about its potential benefits or what's the beef.

By Robert Arner

Landfills are the largest source of methane emissions by human activity in the United States, accounting for 37% of these emissions according to EPA's 1997 emission numbers. Landfill gas (LFG) consists of about 50% methane, 50% carbon dioxide, and typically less than 5% nonmethane organic compounds. Since methane is 21 times more effective at trapping heat in the atmosphere than carbon dioxide is, lessening its impact to our atmosphere is vital. Already about 15 million tons of carbon-equivalent (MMTCE, the basic unit of measuring GHG) emissions are captured every year by LFG-to-energy (LFGTE) projects.

While LFGTE projects are a form of pollution control and energy development, there are those who feel that investing in such endeavors undermine composting and recycling programs. Some environmentalist contend that if LFGTE projects get increased subsidies, this will economically stimulate landfill disposal at the expense of organic materials recovery. Also, they argue that promoting LFGTE just adds to the current flaws in landfill design. Finally, they maintain that LFGTE projects are not renewable green sources of power. These environmental critics stress that preventive measures must first be encouraged to keep landfills from cheaply disposing such things as paper, foodwaste, and other large sources that develop methane. Finally, they contend that banning the disposal of the recoverable organic materials out of landfills for composting and recycling is a much better way to lessen global warming. Since almost two-thirds of the waste in the US ends up in landfills, air-pollution control measures are necessary.

Tapping into an alternative energy source via gas-utilization projects from landfills can transform an environmental liability into an energy asset. However, there are many necessary variables in getting more landfills to harness this energy source. In addition to persuading a suitable landfill owner to participate in such a program, engaging community support, establishing partnerships with vendors and energy users, securing a good business plan and financing, and deciding the appropriate type of gas-recovery technology are some of the factors critical to establishing an LFGTE project.

LFGTE recovery challenges us–as members of the nation that has 5% of the world's population yet produces 25% of the world's climate-altering CO₂ (greenhouse gases)–to consider what are the best options to one form of greenhouse gas (GHG) reduction. While polls cite that 80% of Americans support US actions to reduce global warming, many of us are unaware of the LFGTE projects. Also, we can explore various options to lessen GHG pollution from happening in landfills in the first place.

Current Status Report

While LFG has been documented to be a major source of GHG in America, there are more than 335 LFGTE projects operational today. There are another 500 candidate landfills that could support an LFGTE project. The addition of these possible projects could cost-effectively transform their methane to provide energy (projects could be electric and direct use). Transforming these 500 landfills to energy recovery offers a tremendous opportunity to powering 1 million homes for one year and removing emissions equivalent to 13 million cars for one year.

Obtaining accurate numbers on the solid waste industry is difficult. According to the recent Environmental Research and Education Foundation study conducted by R.W. Beck Inc., about 374 million tons of waste were landfilled in 1999, including all nonhazardous waste such as household, commercial, industrial, and special waste; regulated medical and yardwaste; sludge; tires; and construction and demolition debris. Some experts question the accuracy of total LFG data since accurate landfill disposal information is lacking. N.C. Vasuki, CEO of the Delaware Solid Waste Authority, addresses the need to improve the national database since landfills get blamed for high GHG emissions. He notes, "In the November 12, 2001, issue of Waste News, information was provided on three of the four largest landfills in all states of the nation. The annual tonnage received by these 150 landfills, in 2000, appears to be about 99.2 million tons out of the 131.9 million tons estimated in the EPA report. Therefore, the top 150 large landfills receive about 75% of the nation's solid waste discards. The remaining 2,066 landfills appear to receive the remaining 25% or 32.7 million tpy. If these numbers are verifiable, the states and EPA can reduce GHG emissions by concentrating on the top 150 landfills."

One firm that has concentrated on large LFGTE projects is DTE Biomass Energy, which has participated in developing LFGTE projects since 1987. It operates numerous large projects converting LFG into energy. For example, LFG powers a Ford Motor plant and other large industrial energy customers.

LFGTE Does Not Fit Any One Design

LFGTE projects do not fit any cookie-cutter design since each landfill differs–from the owner/operators to its site location, size, and specific waste composition. Each landfill operation has differing waste types, quantities, moisture, and pH. Good candidates for LFG utilization must factor in site characteristics and conditions, quantities and quality of waste disposed, and other specific parameters. Other important considerations include:

• Is an existing landfill near a power grid or industry that could utilize the gas?
• Does it have enough capacity to develop alternative energy projects?
• Will the local community accept this project?

The market dynamics of LFGTE are highly variable since local, regional, and national markets; incentives; and regulations all influence whether these projects are permitted and how they are developed. Ideal LFG situations are when landfills have roughly 1 million mt or 20 ac. of waste in place, usually 30 ft.—plus deep and newer landfill waste (either open or closed within the last five to seven years) since older waste produces less gas. Waste with higher organic fractions contributes to higher quantities and qualities of methane. In addition, lined landfills with claylike soils are ideal. Since landfills are dynamic and no two are alike, however, there are LFGTE projects outside the "norm," as cited in the above ideal conditions.

Current Energy Market

LAG from Colorado's Tower Road Landfill is used to produce green energy.

Since there is no national energy plan, all renewable and nonrenewable forms heavily compete with each other from a regional supply-and-demand perspective. Nevertheless, it should not be overlooked that the world oil supply plays a critical overall force in energy scenarios. How we define LFGTE from a renewable-energy standpoint is another critical economic issue.

Some contend that LFG markets do not enjoy a level playing field with other energy forms that have been more heavily subsidized. The energy market varies in each region, so there is no rule of thumb that works in all scenarios. Also, LFG projects have been established for both energy and environmental reasons–there is no template. LFGTE is directly tied to both fossil fuel and renewable-energy markets, forcing these endeavors to be competitive. Before any incentives, LFG costs an average 3-6 cents per kilowatt-hour (kWh), depending on each project. LFG also requires demand-pull tactics to better commercialize this energy. According to EPA, there are some 500 landfill sites that could economically exploit this resource. Even though all consumer surveys show that the majority of people will pay up to 10% more for renewable energy, this does not translate into money to bank on.

Over the last several years, the energy market has fluctuated wildly as if it were on a roller-coaster ride. Like oil in the late 1970s, the recent natural-gas prices skyrocketed to record highs, only to fall as quickly back to prior levels. California's energy crisis last summer coupled with the downfall of the country's premier energy company, Enron, reflects the instability of this market, making the business community reluctant to invest heavily in energy companies.

Green-Power Debate

Green power is any renewable form of energy, and some argue that LFGTE should not be considered as such. While today there is no uniform or widely accepted state or federal definition of green power, different renewable industries are lobbying to standardize such a definition. One challenge is to best define green ownership depending on where it is produced and sold. In most states this includes wind, solar, geothermal, hydro, and biomass (including LFG), but Maine, for example, does not recognize LFG as a renewable-energy source. There are a variety of market mechanisms affecting green power.

While LFGTE projects have financial barriers to overcome, there are many avenues to assist these projects–among them loans, grants, renewable portfolio standards, renewable-energy trust funds, and property-, sales-, and use-tax exemptions.

Tradable Allowances for GHGs

Another important area to stimulated LFGTE projects is a newly emerging pollution-trading marketplace where people buy and sell GHG credits. This fast-growing commodity market provides tradable allowances for GHGs. Business executives and economists expect climate-changing gas trading to become the way of the future in the fight against global warming. One global energy broker, Natsource, estimates that 55 million tons of GHGs have been traded since 1996. Very few trades are happening with methane specifically, but the market is growing and the potential is great. In the next several years, this entire GHG market could expand to $200 billion.

LFG has yet to be apart of the GHG emission trading. This GHG exchange is driven by the science documenting our present global warming. Even though it is voluntary at this time, companies are trading tens of millions of tons of CO₂-equivalent energy credits called verified emission reductions (VERs). While this has not happen yet with LFG, VERs are measured by third parties between buyers (such as power companies) and sellers (such as landfills) in the form of renewable-energy certificates, which document the specific ownership of the reduction by exchanging each megawatt per hour of power onto the energy grid.

Twelve states have mandated Renewable Portfolio Standards (RPS), a system that obligates power companies to purchase renewable energy in order to guarantee demand for renewable power. At least 80 utilities around the US offer renewable energy through green pricing; many include LFG. These mandates represent a key driver for green power. Some experts note, however, that the RPS system is flawed and has not generated significant actions in many states (Johnson, 2001). Forty million US households have access to green power through competitive markets or utility green-pricing programs (Vasuki, 2001). In addition, there are options for selling green power from green-power marketers (selling in competitive markets), from green pricing (available in monopoly service territories), or from green tags/tickets.

The green-power market provides the generators with two revenues: electric price and green premium resulting in the green-power price. A renewable-energy source sells electricity to a power company at the nonrenewable market price. The generator receives money from this energy sale in the form of a green ticket. This is verified from its energy meter data. Generators can sell their tickets to power exchange market firms within a year and keep the premiums. These firms act to broker energy service providers in order to trade these emission credits. Finally, a neutral third party verifies and equates the generator's green ticket with the user's energy use to ensure a good accounting of these trades.

At least 17 states offer State Renewable and Clean Energy Funds in the form of low-interest loans, grants, and investments that can be used to assist LFG projects (see www.epa.gov/lmop). Other programs, such as the Green-e Program (www.green-e.org) and EPA's Green Power Partnership (www.epa.gov/greenpower), are also available.

Federal Tax Credits

Another green-power "premium" takes form in a variety of federal incentives. Since both nonrenewable and other renewable energy (wind, chicken litter) have tax credits, the playing field is not level. The expiring federal tax credits awarded under Section 29 of the Internal Revenue Code provided LFG projects with a significant tax stimulus. Through the federal tax credits, 85 new projects came on-line in 1997-1998. New LFGTE projects dropped slightly, to 70, in 1999-2000, compared with 1995-1996, when only 29 new projects were constructed. Critics argue that these credits have been given to projects in states where such energy recovery was already economically justified.

The House of Representatives passed HR 4 that would reinstate these LFGTE tax credits; however, present legislative language needs to be modified (according to the LFGTE lobby). These tax credits can do much to stimulate new LFGTE projects since such economic incentives are created for new energy developers. Proposed congressional legislation containing LFG provisions (S 390, S 596, HR 1863, HR 2511, HR 4) and an express recommendation for LFG tax credits in President Bush's energy plan show significant signs of widespread bipartisan support for all LFGTE credits.

SWANA estimates that Section 45 tax credits would impact 552 possible new LFGTE sites, with an estimated 25% participation rate. They would cost $216 million, with the electricity selling at 2.1 cents/kWh. This credit would spurn 46 new LTGTE projects each year over an estimated three-year period.

Whether or not Congress enacts LFGTE tax incentives next year will have an economic impact on the growth of these projects. A broad federal LFGTE tax credit could provide roughly $700 million in credits for 10 years. Such final congressional rulings will determine the rate of growth of this technology. Some industry experts contend that the stimulus to recover these lost GHGs may hinge on whether Congress renews its expiring federal tax credit that has stimulated much of this energy industry.

Another trend is the shift from electric to direct-use LFGTE projects because of the loss of tax incentives. While electricity projects represent two-thirds of all operational projects, the trend is toward direct-use applications–mainly a result of no tax credit.

Conflicting Views

Some critics argue that landfill tax credits have gone to states that have favorable economics (e.g., high electric rates) and that such projects would have been installed anyway. The Grass Roots Recycling Network (GRRN) claims that such a subsidy would divert funds from the US Treasury necessary for other important and more essential environmental projects. For example, GRRN contends that this credit would lower tipping fees that would reduce financial support for composting programs. Also, since it claims that gas recovery systems are unlikely to recover much more than 10-25% of the total gas emissions, the rest will be emitted uncontrolled. This challenges the assumption that 75% of the gas is captured by LFG extraction systems. Those gases include not just methane but also carcinogenic volatile organic compounds (VOCs) in the methane that is transported into the atmosphere. The only real solution is to eliminate the source of methane production–namely by source-separating the entire organic fraction for composting or, if you want, bioconversion controlled in-vessel.

The GRRN position is summarized below in its white paper titled, "Why Tax Credits for Landfill Gas Energy Recovery Is the Wrong Strategy":

• Most LFGs from decomposed trash are not captured but are released into the air.
• The obsolete practice of landfilling organic matter leads to LFGs.
• The real issue is how to eliminate organic material from landfills.
• The solution is expanded composting and other bioconversion technologies. Tax credits for disposal will forestall positive alternatives.
• LFG energy recovery should be required, not subsidized.

The National Recycling Coalition also objects to these credits and has written to Congress against such a subsidy for landfills.

New Technologies

Many technologies are available to convert LFG into a variety of energy sources. Direct thermal, reciprocating engine, leachate evaporation, gas turbine, cogeneration, vehicle fuel upgrading, liquefied natural gas, fuel cells, methanol synthesis, and other emerging technologies are either being constructed or planned. Using LFG in place of natural gas in boilers is well tested and documented in the last two decades through cost-effective retrofits. In addition, there is a shift to more direct-use projects.

An attractive new technology is microturbines. This offers smaller landfills more options to produce electricity close to generation sites. Typically, internal combustion engines for LFGTE run 800 kW, whereas larger and conventional turbines run for 3 mW and higher. Microturbines can fill an important niche for power generation for individual unit sizes in the 30- to 300-kW range.

In southern California, Capstone operates two LFGTE off-utility grid projects. These two projects are city-owned landfills and use 60 microturbines. The City of Burbank converts one-third of its present residential trash into electricity. The Department of Water and Power owns this project with financing from the city and a one-third grant from the State Energy Office. These microturbines are relatively expensive technology, operating at greater than 5 cents/kWh with 7 cents/kWh. The other landfill is Los Angeles Lopez Canyon. The Los Angeles Department of Water and Power bought these microturbines to reduce their excessive NO₂ emissions.

Another emerging technology is bioreactor landfills that accelerate the creation of LFG. Recirculating leachate and pumping air into bioreactor landfills will accelerate the stabilization of organics by increasing microbial degradation. Bioreactor landfills transform and stabilize the readily and moderately decomposable organic constituents of the wastestream by enhancing microbiological processes, thus increasing the amount of waste disposed. Bioreactors produce more energy value and thus additional LFG potential. Bioreactors have since shortened this closure time frame by one-third, as they work much faster than normal landfills and can produce more LFG in a shorter time period. There is an opposing view, however, that bioreactors are not the best environmental course of action, since composting these organics is a more beneficial course of action.

LFGTE has stimulated many other types of technologies, such as carbon-dioxide recovery systems and siloxane-removal technologies (organic compounds that contain silicon impair and shorten LFGTE projects that are found in personal hygiene products). Also, extraction-well cleaning methods are providing significant cost savings and improved extraction efficiency for LFGTE projects.

Small Landfills

There are hundreds of landfills with less than 3 million tons of waste in the US. More than half of the present LFGTE projects are at smaller landfills. Such projects can possibly solve existing problems. In Saratoga, NY, LFG is used to heat the city's ice-skating rink. Another example is the Davidson, PA, landfill, which had a costly leachate problem. By using the LFG on-site to fuel technology to evaporate this leachate, an economical solution resolved this costly problem.

One nationally recognized example is in the western mountains of North Carolina at a location called the EnergyXchange. This innovative environmental-improvement project showcases a nonprofit community art center featuring pottery kilns, glass furnaces, and greenhouses heated by Avery County's LFG. This is a great example of some innovative folks in the Blue Ridge Resource Conservation and Development Council creating a dynamic economic development partnership that raised more than $1 million to build an environmental visitor/business center with aquaponics, greenhouses, and craft facilities from LFGTE that in the coming years will capture $1 million in lost methane gas.

Landfill Methane Outreach Program (LMOP)

EPA's LMOP has been a tremendous force in developing public/private efforts to encourage the development of these renewable projects. Currently, more than 280 partners have signed voluntary agreements to work with EPA to harness this power. Since 1995, the LMOP has assisted more than 190 LFGTE projects. In 2001, LFGTE projects prevented the release of 2.7 MMTCE, with an environmental equivalent of removing the emissions of more than 2 million cars from the road for one year. The LMOP provides free technical assistance and technology transfer (www.epa.gov/lmop).

Other Developments

Stimulating the market and building demand is happening through a variety of regional and national organizations. For example, the Mid-Atlantic Renewable Energy Coalition is stimulating consumer demand for renewable power, including LFGTE, with a million-dollar Web, radio, and print campaign in February 2002 in the Philadelphia and Pittsburgh media markets.

A major power utility, AMP-Ohio, developed an energy pool to market 35 MW of LFG electricity so that the 22 landfill purchasers in 37 municipalities developed a better market for its LFG and greater efficiency in its operation.

Future Trends

With the price of oil rising dramatically, the question is not if but when we will have another energy crisis. What is lacking is a better life cycle understanding of how such project development might promote more recycling and/or composting and prevent more organics from being disposed in landfills in the first place. Today's cost-associated regulatory compliance to manage LFG under the Clean Air Act is just one of the reasons for stimulating LFGTE projects. Again the issue of global GHG is another case of not if but when the pressure will increase to the point that it is absolutely necessary to be more assertive in capturing this renewable-energy resource. Besides reducing methane emissions, LFG recovery lessens GHG, smog, and odor.

The pressure to comply with environmental standards provides a motivation for LFGTE projects. The New Source Performance Standards and Emissions Guidelines also stimulate growth in LFGTE projects. From a regulatory perspective, they bring in more stringent regulations and increase compliance costs. States will have to raise permit fees to cover recordkeeping, inspection, and enforcement. Mercury, nonmethane VOCs, and dioxin emissions are some of the future air issues (Vasuki, 2001).

Also there is the liability interpretation under the EPA's WWW regulations regarding ownership of LFG operation. EPA requires that third parties be notified by landfill owners/operators when accepting LFG. The responsibilities of landfill owners/operators and LFG developers need to be more clearly defined in the current EPA regulations so that everyone knows what their legal obligations are.

Conclusion

We know that the LFG industry will grow; now the uncertainty is how much. How effectively the environmental lobby will oppose LFGTE tax credits and LFGTE as a renewable-energy source is another unknown. Each year LFGTE projects are expected to grow. At issue is whether an additional 10-30, 20-40, or 30-50 projects will be operational each year. We will just have to wait and see due to many factors, including federal tax credits. One thing is for sure: As the earth's temperatures increase, so will the debate on how to best proceed with LFGTE projects. Such model examples as the EnergyXchange Renewable Energy Center show that innovation, partnerships, and engaged community action result in such stewardship. Executive Director Stan Steury of the EnergyXchange quotes a Nigerian Chieftain regarding their shared project vision: "I conceive that land belongs to a vast multitude of which many are dead, few are living, and countless numbers are yet unborn." Hopefully, future generations will be able to look back at how we balanced the various economic, environmental, and other considerations so that LFGTE projects have best benefited our world.

References and Suggested Reading

Foroohar, Rana. "The New Green Game." Newsweek, August 27, 2001.

Johnson, Kurt. "Green Power: Who's Selling, Who's Buying." Landfill Methane Outreach Program, Green Power Workshop, Washington, DC, December 12, 2001.

Peters, Jerry. "Banking on Green Power Premium: An Investor's Perspective." Landfill Methane Outreach Program 5th Annual Conference and Project Expo, Washington, DC, December 13, 2001.

Vasuki, N.C. "US Reliance on Landfills." Landfill Methane Outreach Program 5th Annual Conference and Project Expo, Washington, DC, December 13, 2001.

Robert Arner is a waste management expert and soil and water conservation director for Shenandoah County, VA.