|Corn-Burning Benefits Hinge on
How It's Grown
(Note: Gang Green is raging because -- well, er, because .... -- who knows why they're raging, but they're upset that corn might take the place of fuel oil, and that would mean their 'envisioned' rural playgrounds might just have to remain in production agriculture. Anyone have a crying towel?!!)
January 27, 2003
By Rick Weiss
Washington Post Staff Writer
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It's the cynic's Golden Rule that no good deed goes unpunished, and no group knows it better than those well-intentioned, ecologically oriented citizens who heat their homes with special corn-burning stoves instead of natural gas or oil. Their goal is to reduce emissions of greenhouse gases that contribute to global warming. But their approach has critics fuming.
"This is an example of how stupid society is," one irate energy analyst wrote recently on a Web site, echoing comments from many others after articles about corn burners appeared in several U.S. newspapers, including The Washington Post. "More gasoline was spent to grow the corn than the [energy] delivered to heat the houses," wrote Ken Bosley, of Sparks, Md.
In fact, corn cultivation in this country is, for the most part, an energy-consuming environmental disaster, said David Pimentel, a professor of ecology and agricultural science at Cornell University. "Corn is the number one cause of erosion or total soil loss in the United States," he said. "It uses more fertilizer than any other crop. It's the largest user of insecticides. And it's the largest user of herbicides."
Yet a careful analysis by several experts in soil science and agricultural economics, including Pimentel, indicates that proponents of corn-burning are largely right in claiming that their approach is both easy on the pocketbook and good for the Earth -- as long as the kernels are grown and transported in an environmentally sustainable way. That means minimal use of chemical fertilizers and insecticides, no-till cultivation to reduce tractor use, and reliance on locally grown or stored corn.
"A lot of people are using it and it works," said Helmut Spieser, an engineer with the Ontario Ministry of Agriculture and Food, who studies the pros and cons of burning corn. But for people to calculate whether corn burning makes ecological sense for them, he said, "You really need to use a sharp pencil."
The planet would benefit from a reduction in Earth-insulating greenhouse gases -- especially carbon dioxide, or CO2, the major byproduct of combustion -- scientists say. The National Academy of Sciences has concluded that the Earth could warm as much as 10 degrees in the next century if current emission trends continue, wreaking major ecological and economic havoc.
Home heating contributes modest amounts of greenhouse gases compared with what power plants and motor vehicles contribute. Homes account for about 7 percent of the nation's energy budget, and home heating and cooling accounts for about 40 percent of that, most of it for heating.
But in the firm belief that every molecule of CO2 counts when it comes to saving the Earth, climate activist Mike Tidwell and soil scientist Diana Friedman took Spieser's advice. The Takoma Park residents sharpened their pencils and worked with other experts to see just how much they could reduce their CO2 emissions by installing corn-burning stoves in their homes.
The stoves, which look like modern wood-burning stoves and sell for about $2,000, feed dried corn kernels one at a time into a combustion chamber. Heat spreads by convection and, depending on how the house is laid out, travels with varying efficiency to other rooms.
Friedman is the first to acknowledge that their analysis is not perfect. But several independent experts said they found the numbers mostly convincing.
The big advantage is that corn absorbs CO2 from the atmosphere while growing, offsetting the CO2 it releases when burned. By contrast, oil and gas are the remains of plants that lived so long ago that only an Enron accountant would dare count the CO2 they once absorbed. Those fuels are a one-way street of CO2 release, while burning and growing corn constitutes a roughly balanced carbon cycle.
Roughly, because CO2 is released not only by the burning corn, but also by the tractors and farm trucks used to grow the corn and to make insecticides, herbicides and fertilizers. To minimize those releases, Tidwell, Friedman and eight other Takoma Park families buy their corn collectively from a Mount Airy farmer who uses manure from his turkeys to fertilize the corn. He also leaves the stalks on the ground to minimize atmospheric release of their carbon; uses no-till techniques; avoids insecticides; and delivers 20 tons of dried kernels at a time to a silo the families erected in town, which makes the most of the diesel fuel his truck uses.
According to the group's analysis, the growth, transport and combustion of a ton of dried kernels actually drew more carbon from the atmosphere than it released, with a net reduction of 484 pounds of CO2. Burning natural gas to get the same amount of heat, they calculate, would spew 1,980 pounds of CO2 into the air. Oil would release 2,701 pounds of the gas.
Experts quibbled with those numbers -- saying, for example, that the analysis overestimates the amount of heat released by burning corn. Even after the kernels have been dried (as they must be to burn well and to prevent rotting in storage) they are still about 15 percent water, said Dennis Buffington, an engineer at Penn State University. So the reduction in CO2 emissions compared with those of oil or gas is less dramatic than Tidwell and Friedman calculate.
Moreover, few U.S. farmers are as careful as Mount Airy's Gary Boll with their use of tractors, fertilizers and other inputs. Friedman estimated that Boll releases 132 pounds of CO2 to raise a ton of kernels. But that's about one-tenth the typical level for U.S. farmers, said Pimentel, noting that corn proponents also fail to count the energy used to produce hybrid corn seed.
Pimentel contends that the most efficient fuel around is sustainably grown wood (others say wood smoke has too many particulates). Still, he and other analysts said, corn comes out clearly superior to fossil fuels -- especially since 10 percent to 30 percent or more of the energy in fossil fuels is used to get them from the ground to the household, an inefficiency that Friedman and Tidwell generously ignore in their analysis.
There are disadvantages to corn. A 2,000-square-foot home can go through four tons of corn in a winter -- a volume about six feet by six feet by four feet deep.
"The first few times getting corn, it's recreation. You say, 'This is great. We drive in the country. We load the shelled corn into the car. Isn't this fun?' " Buffington said. "But after that, it's going to lose its recreational value, and it can be drudgery."
And whether it burns corn, gas or oil, a stove cannot heat a big home as thoroughly as a furnace with ducts and fans can.
But the advantages of corn extend beyond CO2 reductions, proponents say. Local corn growers benefit because they can charge as much as $5 a bushel for clean, stove-quality corn, compared with wholesale prices of about $1.25. Even at the higher price, many residents report heating their homes for less than half their old heating bill.
And let's not forget oil's environmental dangers, Tidwell said.
"When 20 tons of corn come barreling down the road and, God forbid, there's an accident, well, what have you got? A corn spill."