Federal efforts to protect the Shenandoah National Park from air pollution have delayed and could halt plans to build more than a dozen electric generating plants that Virginia Power says it needs to meet rising demand for electricity in the state.

The National Park Service notified the state last month that the proposed coal-burning plants would have an "adverse impact" on air quality, visibility and vegetation in the scenic 195,000-acre park, which tops the Blue Ridge mountains between Front Royal and Waynesboro.

The U.S. Forest Service expressed similar concerns about the James River reservation, a wildlife management area in Nelson County.

The state Department of Air Pollution Control now must balance the federal opposition with Virginia Power's need to increase electricity production. To meet rising demand and to avoid buying power from other utilities, Virginia Power expects to raise its output by 50 percent within the decade, company spokesman James Norvelle said..

National Park Service officials, including Director James Ridenour, have criticized plans for more power plants in the state. Shenandoah Park Superintendent J.W. Wade has complained that pollution from more smokestacks will increase acid rain, create more haze and damage air quality in the park, which attracts more than 2 million visitors a year.

State, Virginia Power and federal officials met in Virginia Beach last week to begin working out a compromise that could head off federal objection to at least some of the planned facilities.

"We felt very good . . . . We feel we would be able reach an agreement on a study to indicate a prudent course of action," Virginia Power's Norvelle said.

Park Service officials would withdraw their opposition to the generators if the state orders existing plants to reduce their pollution, said David Haskell, chief of natural resources for the Shenandoah National Park.

"All we want is to not let the air pollution get any worse, and hopefully get a little better," Haskell said. "It's completely up to the state how they do that."

The compromise can't come too soon for the independent companies that have signed contracts to build the controversial plants.

"Our permit has been delayed by a year {because} the state was slow in processing, and then the Park Service surfaced at the eleventh hour," said B. Edward Brammer, president of the Multitrade Group, which is to build a 76-megawatt plant in Hurt, Va., southwest of the park.

The Park Service "has added another level of complexity to the whole situation," said James A. Lowe, vice president of Cogentrix, which is seeking to build a 190-megawatt plant in Richmond and a 220-megawatt plant in Dinwiddie.

The Park Service or a third party, such as an environmental group, can appeal to the U.S. Environmental Protection Agency any state decision to approve the power plants.