Making electricity while the wood burns
Scraps of wood and bits of sawdust -- a sweet-smelling mixture that resembles rich potting soil -- are the stuff from which electricity is made in Wisconsin. IT is being burned at the Lake Superior District Power Company in Ashland.
This makes the electric company the first stockholder-owned utility in the United States to generate electricity by burning wood, according to William P. Maki, vice-president in charge of planning.
The only other electric company in the country to burn wood is the municipally owned Burlington (Vt.) Electric Department, and it burns wood harvested for the purpose.
By using local industrial wood residues, such as bark, ships, and sawdust, to fire steam turbines, the Ashland company plans to produce about 20 million kilowatt-hours of electricity annually. That is 3 to 4 percent of the utility's total requirements -- enough electricity to meet all of the needs of the residential customers in a city of 10,000.
Mr. Maki estimates it would require clear-cutting 10 square miles of forest every year for the company to meet just 40 percent of its electricity demand by using wood.
"As far as being a cure for the energy problem, I don't think wood burning is going to do that," he said. "But as far as a small project like this goes, it will help."
Basically, federal officials studying the subject agree with him.
Andrew Baker, a chemical engineer at the US Department of Agriculture's Forest Products Laboratory in Madison, Wis., said wood used as fuel could be expected to play a small but significant role in solving the national energy problem.
Mr. Baker cited a recent report of the Madison laboratory which concluded that, if half the unused wood residue could be collected economically, it could be converted to meet about 7 percent of present US energy needs.
The Lake District Power Company was attracted to wood nearly a decade ago because of the company's unique geographic location. The 10 northernmost counties in Wisconsin, roughly its service area, are about 72 percent forested, according to a recent study on timber availability prepared by the Northwest Regional Planning Commission in Spooner, Wis. Logging is the foremost industry in the region, and about half of the timber harvested is unused because it does not meet commercial standards.
"We began researching this project in 1972 because we felt we were in a unique position with all of the wood waste here and we realized it could serve as a source of cheap fuel," Mr. Maki explained. "According to our company research, there are about 175,000 tons of waste wood available annually within a 60-mile radius of the plant in Ashland." The company plans to use about 40,000 tons a year.
With wood waste purchased at $1 a ton from a Louisiana Pacific Corporation stud mill and trucked two miles for $2.25 per ton, the company expects to pass along $300,000 a year in fuel cost savings to its 39,000 customers.
The average household will have its bill reduced by about $9 a year. The cost of converting one of the company's five cola-burning boilers to use wood that is blended with coal was $850,000. Company officials expect to recover the investment in five years.
Wood scrap used as fuel is now 75 percent cheaper than coal in this region. A ton of wood scrap contains about 9 million Btu of energy. It would cost about
Use of wood scrap for fuel has support in the US Environmental Protection Agency. But JAmes H. Phillips of Chicago, the EPA energy coordinator for Region 5 (Illinois, Indiana, Ohio, Wisconsin, Michigan, and Minnesota), said that the harvesting standing trees specifically for fuel raises grave concerns.
"When you're burning wood waste, that's not thing, but when you're burning wood that was cut for nothing but fuel, that's quite another thing," he said. "One can strip the wood supply of the nation in a big hurry."
Even using wood residue has raised serious concern among some forestry experts. Arthur Brauner, executive vice-president of the Forest Products Research Society in Madison, points out that removal from the forests of logging debris, which otherwise would decompose to return organic matter to the soil, robs the soil of humus that is necessary for sustained tree yields.
"The question is, "What are you doing to the soil?'" Mr. Brauner said. "And the answer is that you're doing some very dastardly things. It's one thing to use mill waste and quite another to bring in waste from the forest floor."
Mr. Brauner added that the potential for critical problems axists on the steep-sloped West Coast, where serious soil erosion could eventually result.
Elmer Lee, chief of US Energy Department's existing-utilities branch, says, however, that at this time his division is not concerned about the future effects on the environment of wood used as fuel.
"We are only concerned with getting people off imported gas and oil," he said. "We're not concerned with how they're doing that." He adds that the Wisconsin power company's switch to wood is in the spirit of the federal Power Plant and Industrial Fuel Act of 1978, which encourages major energy users to find alternative fuels.
At the Wisconsin utility, during periods of peak power demand the furnace will still use coal entirely, because it was built to burn that originally and continues to use it most efficiently.
Wood will be used at times the power requirements are lower. Original plans called for the furnace to use from 30 to 40 percent wood. Now company officials find it can use up to 50 percent.
Encouraged by the success of the project, the Ashland power company has already applied to the state Public Service Commission for permission to convert a second coal burner to handle wood.
The Ashland-area environment will benefit from the switch, since wood burning is cleaner than coal. There is virtually no sulfur in wood, which can pose a health hazard, the EPA's Mr. Phillips said.
"As long as a company can meet all of the particulate-matter regulations, the department encourages burning wood because it is less harmful than coal," said Daniel Schramm, an environmental engineer with the Wisconsin Department of Natural Resources, who is in charge of enforcement and plan review for air quality.
Harmful chemicals in wood, such as creosote and turpentine, which could pose a potential pollution hazard, are totally combusted in the furnace because of the high heat (2,000 to 2,500 degrees F.) that results from burning wood blended with coal, according to all of the authorities.