Converting trash gas into energy gold
Converting trash gas into energy gold
http://edition.cnn.com/2006/TECH/05/25/landfill.gas/index.html
ATLANTA, Georgia (CNN) -- The Trash you toss in the garbage could
end up powering your lights, computer and washing machine, because
in the world of alternative energy, one man's Trash is another
man's treasure trove of fuel.
With the growing concern for U.S. dependence on foreign oil and
recognition of shrinking fossil fuel reserves, new attention is
being focused on renewable sources of energy.
One such source that already is being converted to electricity is
landfill gas.
According to the Environmental Protection Agency, every person in
America produces an average of 4.5 pounds of garbage per day. Much
of that Trash goes into landfills, which are the largest
human-related source of methane in the United States.
In 1994, the EPA formed the Landfill Methane Outreach Program
(LMOP) under the United Nations Framework Convention on Climate
Change. LMOP Team Leader Brian Guzzone said since methane is both
a pollutant greenhouse gas and a source of energy, it offers a
good opportunity to reduce greenhouse emissions and provide
energy.
About 50 percent of all of the waste that we generate as a society
today is put into municipal solid waste landfills, Guzzone said.
The EPA encourages the capture of the resulting landfill gas and
the energy produced from it.
The federal government has partnerships with more than 500
utilities, states, private businesses and communities. "The EPA's
role is to work with communities that have landfills and help them
realize the potential opportunity of their landfill," Guzzone
said. That includes providing materials, technical services and
community outreach.
Trash into gas
The process of converting landfill gas into energy is relatively
simple. A series of wells sunk into a landfill collect the gas,
which is then used to burn in engines and boilers, heat
greenhouses, fuel vehicles, etc. Guzzone said landfill gas can be
used just as traditional fuels such as coal and natural gas are
used. "It's comparable to natural gas," he said.
In 2005, there were 396 operational landfill gas projects in the
United States, Guzzone said. According to the EPA Web site,
two-thirds of the current projects are being used to generate
electricity, producing approximately nine billion kilowatt-hours
per year.
The other third of operational projects supply gas for direct-use
applications, such as fueling boilers, engines and greenhouses.
In total, the projects produce the energy equivalent of
electricity for 725,000 homes or heat for 1.2 million homes.
One of LMOP's partners is textile manufacturer Interface Flooring
Systems.
Located in LaGrange, Georgia, the company buys landfill gas from
the city-owned landfill. The gas is sucked from the 90-acre
landfill by 53 pipes, compressed and piped 10 miles to the carpet
production plant where it is used as fuel.
David Gustashaw, Interface's vice president of engineering,
stumbled upon the project while trying to find cost-efficient
sustainable energy. "I got tired of hearing what were considered
to be green renewable opportunities always costing more," he said.
After Gustashaw ruled out other alternative energy sources for
practical reasons, the only option left on his list was landfill
gas.
It turned out that landfill gas was the perfect fuel for his new
production plant, which started operating last year.
Gustashaw's goal in approaching the project was to ensure true
sustainability in its environmental, social and financial impacts.
By converting air waste into energy, Interface has reduced its
dependence on natural gas by 20 percent and reduced greenhouse
emissions from the landfill, Gustashaw said.
Socially, "the city is generating a revenue stream from something
they were throwing away," said Gustashaw. "So now the city has
more money for services for the residents."
On the financial side, the initial financial outlay for new
equipment for the project was in the $2.5 to $3 million range.
Gustashaw said that both Interface and the city will be able to
recover the investment. The company expects to recoup its capital
in two to three years, the city in four to five years, he said.
Gustashaw believes that his project pioneered the way for
smaller-scale projects. On a much larger scale, Guzzone said that
the fastest-growing segment interested in landfill methane is the
corporate community of heavy fossil fuel users of natural gas.
But it's not a panacea for the nation's energy challenges. Both
Gustashaw and Guzzone said that landfill gas projects are
site-specific. Depending on the size and energy needs of the
project, landfill gas may or may not be the best and most
cost-effective alternative energy.
Nor is landfill gas expected to replace foreign oil. Because
landfill gas is so site sensitive, Gustashaw said the best
approach to offsetting our dependence on foreign fossil fuels
involves a combination of alternative energy sources, including
solar, wind, water, and geothermal power, as well as landfill gas,
according to which resource best fits the particular situation.
One disadvantage to landfill gas is that though it's cheaper than
natural gas, it has less than about half the heating capacity.
However, neither Guzzone nor Gustashaw acknowledge any downsides
to landfill gas energy when used in conditions that make it a good
option.
"You're taking what was a liability and turning it into an asset,"
Guzzone said.
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