Renewable-energy advocates have discovered electricity in some unlikely places: Pig manure and decaying garbage. Both types of waste are dirt cheap, readily abundant and loaded with energy. That's because as waste decays, it emits methane, an odorless, flammable gas that can be burned to run a generator.
Renewable-energy advocates have discovered electricity in some unlikely places: Pig manure and decaying garbage.
Both types of waste are dirt cheap, readily abundant and loaded with energy. That's because as waste decays, it emits methane, an odorless, flammable gas that can be burned to run a generator.
Two companies are set to start burning the gas and generating electricity under the first two methane projects promoted by the N.C. Green Power program. N.C. Green is a nonprofit that collects donations from the public and distributes the money to renewable energy projects, such as solar and hydroelectric power.
Methane Credit, with offices in Charlotte, expects to start generating power in October at the Wayne County landfill. The rotting trash will put out enough electricity to fully power about 500 homes annually, officials say.
Smithfield Foods plans to create electricity from pig droppings next month on a farm in Magnolia. The manure is expected to generate electricity for 70 homes. It takes 125 porkers to produce enough waste to power one home.
N.C. Green Power subsidizes only projects that make electricity for sale to utilities in the state, not those that make electricity for their own use. Even a small solar unit in a private residence can be rigged to send the power back to power lines instead of to appliances. And there's a market for small quantities of electricity: Utilities such as Progress Energy and Duke Power regularly buy electricity on an as-needed basis from other providers when their plants are shut down for maintenance or when demand spikes.
Companies working with N.C. Green Power sign contracts with major utilities in their area, usually for five years or more. The energy generated by the Wayne County landfill, Smithfield Foods and other N.C. Green Power projects flows out to the power grid and is distributed for general use.
N.C. Green Power "has the virtue of displacing fossil fuel or nuclear generation," said John Delafield, owner of Landmark Renovation & Building in Apex, which builds solar homes in N.C. Green Power's program.
"The promise of this is extraordinary," Delafield said.
It may sound like an alchemist's fantasy of turning dross into gold, but the pioneers say that methane gas has the added benefit of eliminating pollutants -- either pig waste or landfill gases that have to be burned off anyway.
"We're looking for a profitable way to treat pig manure," said Garth Boyd, director of environmental technology for pork producer Smithfield Foods.
In most cases, small alternative energy projects are impractical without subsidies from N.C. Green Power. The group depends on public support, and most of its 7,000 donors are customers of Progress Energy, Duke Power and other utilities. They typically agree to donate in $4 increments on their monthly bills. In addition, businesses in the state such as GlaxoSmithKline, Eisai, IBM and Lowe's Home Improvement pay into the program.
Even with the subsidies, it will take several decades for these small generators to recoup their upfront equipment costs, similar to the length of time it takes a utility to pay off a power plant.
N.C. Green Power has only five alternative energy systems online now -- three solar units, a wood unit and a hydro-electric system with two dozen water mills. (There are no wind generators in the state's mix because the best spots for wind turbines in North Carolina -- the breezy sea coast and the mountains -- are environmentally and politically sensitive.) Utilities in North Carolina pay these private distributors the production cost: Duke Power pays about 2.5 cents per kilowatt hour and Progress Energy pays about 3.5 cents.
On top of that, N.C. Green Power pays private generators up to 18 cents per kilowatt hour, depending on the energy source. Solar gets the most -- 18 cents per kilowatt hour -- because it's the costliest. The subsidies are structured to relieve the private energy generators of some financial burden.
"That makes it so it doesn't hurt horribly bad," said N.C. Green Power resource manager Bob Zickefoose.
The upcoming methane projects will quadruple N.C. Green Power's output this year. The system now pays for 1.5 million kilowatt hours of electricity a year, or enough to power about 125 residential homes. By year's end, it will be paying for 7.7 million kilowatt hours, enough to power about 650 homes. Progress Energy, by comparison, has 1.4 million customers in the Carolinas. The utility generated 60,275,436,000 million kilowatt hours in the Carolinas in 2004.
The Wayne County Landfill project, with a subsidy of 1.9 cents per kilowatt hour from N.C. Green Power, will pay off its $1 million debt in about a decade. The landfill's reservoir of methane gas is not unlimited. That buried garbage will eventually decay, giving the landfill about 20 years of methane-gas emissions.
Pig manure will last as long as there are pigs. N.C. Green Power is paying Smithfield Foods 3.3 cents per kilowatt hour. The company forecasts a 40-year schedule to pay off its $600,000 investment in equipment.
Smithfield Foods converts a tiny portion of its manure into electricity. Most of the manure is treated and turned into organic fertilizer.
"North Carolina has a vast resource of indigenous energy supply," said Jim Voss, president of Methane Credit. "North Carolina has a massive agricultural sector. Between the pigs and the chickens, they produce a significant amount of waste."
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Source: Knight Ridder/Tribune Business News