Utah Power & Light Co.'s Gadsby plant, located off North Temple at about 1300 West, is back in operation.

Idled in 1987, the plant has been operating since Feb. 25 and is now using natural gas instead of coal to produce electrical power. One generator of the three-generator plant is producing an around-the-clock average of 100 megawatts of power, a company official said Wednesday.But, contrary to one news report, the plant was not idled because of air-quality concerns over burning coal in a metropolitan area, John Serfustini, a UP&L spokesman, said.

"The plant was idled because of the lack of sufficient demand to keep it running. We started to reduce its output back in 1985, and between 1985 and . . . we eventually curtailed (the plant) into complete inactivity," Serfustini said.

He said the plant now does not emit any smoke. Only water mist is visible coming out of the stacks on a cold or humid day when atmospheric conditions are below the dewpoint, Serfustini said.

Burnell Cordner, director of the Utah Department of Health's Bureau of Air Quality, Wednesday confirmed the UP&L statement about the Gadsby plant.

"We (the State Department of Health) did not close the plant down. The decision to stop using the Gadsby plant was an internal (UP&L) decision," Cordner said.

Cordner said it would be better if all power-producing facilities were located in outlying areas. But he said the state doesn't have the right to require that.

With the plant now burning natural gas, "it's about as clean as it can get," he said.

Serfustini said the generator now being used has the capacity to burn either natural gas or coal. The plant is using between 26 million and 27 million cubic feet of natural gas daily, he said.

When the plant discontinued operation in 1987, it was burning only coal but was also equipped to burn natural gas, Serfustini said.

"We are very pleased with being able to bring this plant out of the mothballs as quickly and efficiently as we did. We have held the plant in reserve for the day when it would be our most efficient source of new power, and we are pleased that that day has arrived," he said.