Clean Air Act regulations will force costly changes for at least one Southeast Missouri power plant, while the new rules will have little impact on some other generating plants in the region.

Associated Electric Cooperative Inc., based in Springfield, Mo., has announced plans to switch to a low-sulfur coal supply for its New Madrid power plant in order to comply with sulfur dioxide emission limits mandated in amendments to the Clean Air Act passed in November 1990.

But the Sikeston municipal power plant could actually benefit from continuing to burn high-sulfur coal while Southeast Missouri State University's power plant and the Jackson city power plant would not be effected by the regulations.

Power plants with units below 75 megawatts of generating capacity are exempt from the emission requirements, said Art Wallhausen, assistant to the president at Southeast. "Our generating plant has a capacity of 10 megawatts, so we are far below the cutoff."

Jackson has a 20-megawatt plant powered by diesel generators. A spokesman for the Jackson power plant said existing diesel-fueled generating units are not effected by the Clean Air regulations. However, if the city installs new generators, they would come under the Clean Air Act, he said.

As to Associated Electric, burning low-sulfur coal is cheaper than adding scrubbers, equipment designed to lower emissions from burning high sulfur coal, said Martin Griffin, a spokesman for the utility cooperative.

"It's estimated it would cost $200 million for scrubbers on the New Madrid units, compared to $80 million for converting (the plant) to western coal," he said Thursday from the Springfield office. "There is a significant cost there."

The New Madrid plant has two 600-megawatt generating units.

The $80 million cost includes not only converting the plant to burn the low-sulfur coal, but also constructing a railroad spur and unloading facility, he said.

Currently, the plant receives its coal supply by Mississippi River barge from mines in Illinois. But the plant will receive the Wyoming coal by rail.

Approximately one train of 115 cars of coal can be expected daily after the plant reaches full production.

Although acid rain legislation doesn't take effect until January 1995, shipments of the Powder River Basin coal will begin arriving at the New Madrid power plant by rail in April 1994 in order to build up storage piles so the switch can be made without interruption, utility officials said.

Griffin said that while the change is costly, the cooperative has been setting aside funds to pay for it. As a result, he said, Associated customers won't see a hike in electric rates.

Changing to a low-sulfur coal will actually result in operating cost savings because of cheaper mining costs associated with extracting coal in Wyoming as opposed to coal from Illinois, he said.

"Cost control is very important to Associated,' said Jim Jura, the utility company's general manager. "Keeping rates low in the rural areas contributes to economic vitality. Changing to a low-sulfur fuel supply at New Madrid increases the viability of Associated's operations there," he said.

The sulfur content of the Wyoming coal will allow an 89 percent reduction in sulfur dioxide emissions over the current coal supply at the New Madrid power plant, Jura said.

Associated Electric is the wholesale supplier to 43 electric distribution cooperatives, serving 1.2 million consumer-members in Missouri and southeast Iowa.

While the Clean Air Act means costly changes for Associated, that's not the case with the Sikeston municipal power plant.

"We are in a really good position," said Randy Pick, plant engineer. Pick said the plant has had scrubbers in place since it began operating in September 1981.

As a result, it can continue to burn high-sulfur coal from Illinois and still meet emission requirements without having to make costly changes, said Pick.

Pick said the 235-megawatt plant will have to upgrade its existing emission monitoring equipment as of 1995.

By the year 2000, the plant will have to meet a tonnage limit on emissions. That limit has not been set yet, he said.

"Basically for every pound of coal, we can emit a given amount of sulfur," Pick explained.

"We will not have to change fuel. We will not have to change operations or add a lot of equipment," he said.

Under the Clean Air Act, plants are given "allowances" as to sulfur dioxide emissions. The Sikeston plant is in the 5,000 to 9,000 tons-a-year range.

"We know we can scrub well enough so we will have a lot of allowances left over by the end of the year," he said. Those allowances, in turn, can be sold to other power plants.

Pick said plants will be charged a fee based on the tons of sulfur dioxide emitted, up to a maximum of $100,000 to pay the cost of administering the Clean Air program.

For many power plants across the country, the new regulations will mean higher generating costs.

"There's no doubt in my mind that the cost of electricity will go up substantially because of the Clean Air Act," said Pick.

But, he said, the regulations will also lead to greater use of western coal, which, in turn, will result in decreased prices for high-sulfur coal. The major cost of electrical production is the cost of fuel to generate the power, he said.

"Our cost will be going down while almost every other plant in the country will see their costs going up," said Pick.