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Landfill Gas Energy FAQ
- What is the role of landfill gas in Green Power?
- What is landfill gas, and how is electricity generated from it?
- Does burning landfill gas have other benefits?
- How much energy can a landfill produce?
- How long will a landfill continue to produce gas?
- Does using landfill gas to produce electricity encourage a throwaway society?
- How does the cost of landfill gas energy compare to that of traditional electricity?
What is the role of landfill gas in Green Power?
Landfill gas is a relatively inexpensive resource that can help lower
the cost of green power when combined with solar and wind energy. As Green Power
Switch gets under way, electricity from landfill gas will provide the largest
proportion of its power. That amount will decrease over time as wind and solar
energy grow.Back
What is landfill gas, and how is electricity
generated from it?
Landfill gas, which consists mainly of methane and carbon dioxide,
is produced when organic wastes in landfill sites decay. Landfills over a
certain size are required to flare, or burn, the gas in order to reduce the
hazard of gas build-up. Although landfill gas is primarily a pollutant that
needs control, the methane it contains makes it valuable as fuel to power an
electric generator. Landfill gas was first used as a fuel in the U.S. during
the late 1970s. Since then, the technology required for its collection and
use has developed steadily. This method of producing renewable energy is
now regarded as one of the most mature and successful in the field of green
power.Back
Does burning landfill gas have other
benefits?
If released directly to the atmosphere, methane is a potent
greenhouse gas. In fact, its global-warming potential is some 21 times
greater than that of carbon dioxide. Landfill gas can be flared (the simplest
option), but using it to generate energy encourages more efficient collection
and thereby reduces emissions into the atmosphere. For this reason, energy
recovery from landfill methane, where economically viable, is of considerable
benefit to the environment. Besides reducing global warming, it lessens the
use of conven-tional fuels and reduces regional and local pollution.Back
How much energy can a landfill produce?
It depends on the size and age of the landfill, but production
tends to range from 3 to 8 megawatts. Generators at landfill-gas sites are
very reliable and operate almost year-round with little downtime. So a
6-megawatt plant would produce approximately 47 million kilowatt-hours per
year-enough to supply about 3,200 homes.Back
How long will a landfill continue to
produce gas?
Again, the answer depends on the landfill's age and size. Although
gas is produced once anaerobic conditions are established within the landfill,
it may be several years before the level of production is sufficient to fuel
an electricity generator. Later, as the site ages, gas production (as well as
the quality of the gas) declines to a point at which power generation is no
longer economical. In the case of a typical well-engineered and well-operated
landfill, the expected period of gas production may be as long as 50 to 100
years, but power production may be economically feasible for only 10 to 15
years.Back
Does using landfill gas to produce
electricity encourage a throwaway society?
The part landfill gas plays in energy generation will decline over
time as more and more waste is reduced, reused, or recycled instead of being
added to landfills. As waste pretreatment becomes more widespread, the
biodegradable content of landfill wastes will also drop. Such changes in
waste management, combined with environmental pressures to reduce reliance
on landfilling as a disposal method, will eventually lead to a decrease in
the use of landfill gas as an energy resource.Back
How does the cost of landfill gas energy
compare to that of traditional electricity?
The technology to use landfill gas to power generators and produce
electricity is nearly 30 years old. Consequently, the generation costs are
significantly lower than those of other forms of green power. But landfill
gas electricity is still somewhat more expensive than that produced by
common sources like coal. A typical coal-fired generating unit currently
produces electricity for a little more than a penny per kilowatt-hour. The
cost of producing electricity using landfill gas ranges between three and
four and a half cents per kilowatt-hour.Back
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