New Ethanol Plants to Be Fueled by Cow Manure

New Ethanol Plants to Be Fueled by Cow Manure
Scott Norris
for National Geographic News
August 18, 2006

While a cheap alternative to gasoline may be pie in the sky, ethanol producers in cattle country will soon be reaping the energy rewards of pies on the ground.

Ethanol production plants fueled by cow manure are under construction in Hereford, Texas, and Mead, Nebraska.

The new facilities may have a big impact on the growing debate over the value of ethanol—a liquid fuel distilled from food starches such as corn—as a supplement or alternative to gasoline.

Critics have long argued that traditional ethanol production consumes nearly as much fossil fuel energy as it saves, once all the energy costs of growing and processing corn are factored in.

(Read "Ethanol Not So Green After All?" [July 2006].)

But in Hereford, a cattle town in the Texas Panhandle (Texas map), Dallas-based Panda Ethanol is building a production facility driven by the area's most abundant and least appreciated resource: manure.

The new plant is expected to extract methane from 1 billion pounds (453,000 metric tons) of manure—the product of about 500,000 cows—to generate 100 million gallons (378 million liters) of ethanol, plus ash by-product, each year.

Methane derived from the manure will be burned to generate the steam necessary for processing corn into ethanol.

"We thought it made a lot of sense to use a renewable fuel to create a renewable fuel," said Panda CEO Todd Carter.

"There are literally mountains of manure in the Hereford area."

Cows Crack Corn

By mining those mountains for energy, the Panda facility is expected to save the equivalent of a thousand barrels of oil a day that would otherwise be required to fuel ethanol production.

The manure will come free of charge, courtesy of local feedlot operators for whom waste disposal is a difficult and costly necessity. The Hereford plant will begin operating in the second half of 2007.

Panda has plans to build similar facilities in Haskell County, Kansas, and Yuma, Colorado.

In Mead, Nebraska, a small town of about 600 people 30 miles west of Omaha (Nebraska map), E3 Biofuels is taking the idea of cow power a step further.

Their new facility, set to begin operation in October, will integrate cattle and ethanol production in a highly efficient "closed loop" system.

The E3 operation is smaller than the Panda facilities. Built around an existing feedlot, 30,000 head of cattle will provide the energy needed to produce 24 million gallons (91 million liters) of ethanol a year.

Cattle will be kept in long, covered enclosures with slotted floors, and manure falling through will be pumped directly into the processing facility.

E3 CEO Dennis Langley says collecting the manure immediately eliminates the common problem of water pollution caused by manure left standing in feedlots or spread across farmland.

The process also prevents the atmospheric release of methane, a powerful greenhouse gas, from manure left to slowly decompose.

While Panda relies on an incineration process, E3's manure will be broken down inside an oxygen-free "digester," yielding methane fuel and an ammonia by-product that can be sold as fertilizer.

The energy generated will be used to convert locally grown corn into ethanol and wet distillers' grain, a protein-rich by-product that is fed back to the cattle on site.

Langley says the three-part combination of feedlot, methane generator, and fuel processor will allow the company to make ethanol at less cost and with far better energy return than traditional methods.

"The normal process is, you put one BTU [a unit of energy] in and get two BTU out," Langley said.

"What we do is radical. We put one BTU in and get 46.7 BTU out."

What that means, he continues, is that "producing 1 gallon [3.8 liters] of our ethanol is like producing 23 gallons [87 liters] of traditional ethanol or 15 gallons [57 liters] of gasoline."

Fueling Controversy

With gas prices high and the future of world oil production uncertain, interest in alternative fuels is surging.

But ethanol, a fuel now widely used in Brazil, has been the subject of an often polarized debate in the U.S.

The controversy has been playing out recently both in science journals and on energy blog sites such as The Oil Drum.

Proponents like Silicon Valley venture capitalist Vinod Khosla argue that ethanol can replace gasoline, while opponents counter that not enough agricultural land exists to meet more than a fraction of the country's energy needs.

Cornell University ecologist David Pimentel is an ethanol skeptic and co-author of a study finding that corn ethanol typically costs more energy to produce than it provides.

Pimentel says manure-fueled production does represent an improvement over traditional methods.

"It probably would make [the net energy balance] slightly positive," Pimentel said, though he remains skeptical about the efficiency claims of E3 Biofuels.

"If you omit some of the inputs, you can make it look good. I'd like to see all the data," he added.

But another outspoken ethanol critic, oil industry analyst and blogger Robert Rapier, has endorsed the E3 Biofuels approach, calling it "responsible ethanol."

The 2005 energy bill approved last summer by U.S. President George W. Bush included a controversial mandate for increased ethanol production, and many new facilities are now being built.

Once the Mead facility is up and running, E3's Langley hopes to see small-scale, integrated cattle-ethanol operations spread across the rural Midwest, bringing both environmental and economic benefits.

"We want to build three to five new plants in 2007 and every year thereafter," Langley said.