The Potomac Electric Power Co. is preparing to shut down a major part of its Buzzard Point power plant, once a chief source of the District's electricity, to make way for the opening of its controversial new power plant at Chalk Point in Maryland.

According to a Pepco spokesman, the main generators at the Buzzard Point plant are being closed because they are outmoded and too costly to operate.

However, D.C. People's Counsel Brian Lederer, whose office has been critical of Pepco's plans for the Chalk Point 4 plant, contends it is not necessary to close the Buzzard Point generators. Lederer, who represents District consumers in utility matters, said his engineering experts concluded that the Buzzard Point generators could still be operated.

"Just because they are 40 years old doesn't mean you retire them," he said.

Lederer said Pepco decided to shut down the generators only after his office challenged the company's justification for constructing the Chalk Point 4 plant near Benedict, Md.

"That's absolutely untrue," said David H. Boyce, Pepco's director of corporate affairs.

Boyce said that while the opening of the Chalk Point 4 plant, scheduled for later this year, "makes it possible" to close the oil-fired Buzzard Point generators, "the decision to retire these units is based on our commitment to try to deliver the lowest-cost electricity to our customers." The Buzzard Point generators "are far more costly to operate than Chalk Point 4 would be," Boyce said.

Most of the controversy on the Chalk Point 4 plant has centered on Pepco's decision to burn oil instead of coal there. A hearing officer for the D.C. Public Service Commission, which is conducting a special investigation of the Chalk Point 4 plant at the request of Lederer, recently concluded that there would be a substantial savings to consumers if the plant switched from oil to coal -- a conclusion that Pepco rejects.

Boyce said the hearing examiner held that the shutdown of the Buzzard Point generators was proper.

The Buzzard Point plant at First and V streets SW, which began operation in 1933, has been used in recent years to help supply energy only during peak power periods, primarily during the summer. Boyce said the five steam generators that are scheduled to be retired there have not been used since the summer. The official closing date has not been set but will occur by Dec. 31, he said.

Boyce said the company has begun the gradual transfer of the Buzzard Point plant's 92 employes to other jobs.

"Most of the employes will remain there for some time until the generators are fully decommissioned" later this year, Boyce said.

A substation and 16 turbine-combustion generators, which are used only in emergencies, will remain in operation at the plant, he added.

In addition to the generators being closed at Buzzard Point, a generator is also being shut down at Pepco's other District power plant at 3300 Benning Rd. NE. The Buzzard Point and Benning generators produced about 285 megawatts of electricity. The Chalk Point 4 plant will produce 600 megawatts.