martes, 20 de marzo de 2007

Texas power plant runs on biodiesel

Biofuels Power has opened up a 5-megawatt power plant that runs entirely on biodiesel--and it plans to follow up with another facility that can produce twice as much power.

The Oak Ridge North, Texas, plant runs its three diesel power generators entirely on biodiesel, a form of diesel made from vegetable oil or animal fat, agricultural byproducts that don't have a huge resale value. Other power plants buy biodiesel in limited quantities, but mix it with regular diesel.

By operating strictly on biodiesel, Biofuels says it can become a showcase for alternative energy. A second facility that will produce 10 megawatts of power is already on the drawing boards. Ten megawatts can provide power for about 3,000 homes.

Although biodiesel mostly gets discussed as an alternative to regular diesel for running cars, the inherent properties of biodiesel made from animal fat fit better for power plants. Animal fat biodiesel doesn't function well in cold climates and needs to be kept somewhat warm.

"They really aren't a suitable fuel unless we can come up with a suitable additive to improve these cold flow properties and do it at a low cost. Hence their major use may be for situations where we can keep the fuel supply warm, say above 60 degrees Fahrenheit, such as for heating fuels," Vernon Eidman, a professor at the University of Minnesota, wrote in response to a recent inquiry.

Biodiesel from waste products won't solve the U.S. dependency on oil. The U.S. generates about 2.7 billion pounds of waste vegetable grease a year. If all of it were harvested and converted to biodiesel, it would produce about 350 million gallons of fuel. If half of the inedible tallow and animal fat from slaughterhouses were harvested, another 500 million gallons would be produced, according to figures from Eidman.

The U.S., however, consumed an estimated 62 billion gallons of diesel last year, so these contributions would amount to about 1 percent.

Still, the amount of biodiesel produced in the U.S. will increase in the near future from all sources. Imperium Renewables, which specializes in "fresh" biodiesel, is expanding production, and agribusiness giants, such as Tyson Foods, are looking at building facilities that will take old chicken fat and turn it into fuel.

Other alternative energy experiments in Texas include a series of thermophilic digesters that convert cow manure into natural gas.

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