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 LFG
capture and energy generation from LFG creates a
number of environmental benefits. Final disposal
of solid waste is today one of the most important
problems affecting the Latin American Region in
environmental terms, and the revenues coming from
the commercialization of the energy and/or carbon
credits may help catalyze proper construction and
operation of final disposal facilities
Directly reduces greenhouse gas emissions. MSW (Municipal
Solid Waste) landfills are the largest human-generated
source of methane emissions in the United States,
releasing an estimated 58 MMTCE to the atmosphere
in 1999 alone. Given that all landfills generate
methane, it makes sense to use the gas for the beneficial
purpose of energy generation provided it makes economic
sense. Methane is a very potent greenhouse gas that
is a key contributor to global climate change (over
21 times stronger than CO2.) Methane also has a
short (10-year) atmospheric life. Because methane
is both potent and short-lived, reducing methane
emissions from MSW landfills is one of the best
ways to achieve a near-term beneficial impact in
mitigating global climate change.
An LFG energy project captures roughly 50% of the
methane emitted from the MSW landfill. The captured
methane is destroyed (converted to water and the
much less potent CO2) when the gas is burned to
produce electricity. (CO2 emissions from MSW landfills
are not considered to contribute to global climate
change because the carbon was contained in recently
living biomass. The same CO2 would be emitted as
a result of the natural decomposition process. CO2
from fossil fuel combustion contributes to global
climate change because the carbon has been stored
in the fossil fuels and would not be emitted if
these fuels were not combusted.) The greenhouse
gas reduction benefits of a typical 5 megawatt (MW)
LFG project equate to planting over 80,000 acres
of forest per year or removing the annual emissions
from over 60,000 cars.
 Indirectly
reduces air pollution by offsetting the use of non-renewable
resources. Producing electricity from MSW LFG avoids
the need to use non-renewable resources such as
coal, oil, or natural gas to produce the same amount
of electricity. This can avoid power plant emissions
of CO2and criteria pollutants such as sulfur dioxide
(which is a major contributor to acid rain), particulate
matter (a respiratory health concern), nitrogen
oxides (NOx), and trace hazardous air pollutants.
It should be noted that MSW LFG electricity generation
devices, like all combustion devices, generate some
emissions of NOx, which can contribute to local
ozone and smog formation. Depending on the fuels
and technologies used by the power plant and the
landfill project, the NOx emission reductions from
the power plant may not completely offset the NOx
emitted from the LFG energy project. However, the
overall environmental improvement from MSW LFG energy
generation projects is significant because of the
large methane reductions, hazardous air pollutant
reductions, and avoidance of the use of limited
non-renewable resources such as coal and oil that
are more polluting than LFG.
Provides other local benefits. Collecting MSW LFG
to produce energy improves the air quality of the
surrounding community by reducing landfill odors.
Burning LFG to produce energy also destroys most
of the non-methane organic compounds that are present
at low concentrations in uncontrolled LFG, thereby
reducing possible health risks from these compounds.
Gas collection can also improve safety by reducing
explosion hazards from gas accumulation in structures
on or near the landfill. Generating energy from
existing MSW landfills is also a relatively cost-effective
way to provide new renewable energy generation capacity
to supply community power needs, and can create
jobs that help build the local economy. |
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