For that and other reasons, the Supreme Court shouldn't grant an unusual request by Wisconsin Energy Corp. to hear the case on a sped- up schedule, opponents added.

The foes, which include Racine-based S.C. Johnson & Son Inc. and the environmental group Clean Wisconsin, won an earlier decision in Dane County court blocking the $2.15 billion project.

In court documents filed late Monday, the critics said the utility's predictions of electricity shortages aren't substantiated. Nor was the utility's estimate that the project's cost could rise by $70 million to $260 million, they said.

At issue is the fate of the plants, centerpiece of Wisconsin Energy's plan to help address growing demand for electricity in a state that hasn't built major power plants in a generation.

Wisconsin Energy contends that Dane County Circuit Court Judge David Flanagan was wrong to halt the project. Flanagan ruled that the utility's application was flawed.

The utility "has propagated unjustified fears of capacity shortages and excessive costs," and the Public Service Commission "appears to have fallen under the spell of (the utility's) mantra, disregarding its own analysis that a new coal unit would not be needed until 2011 at the earliest," S.C. Johnson and Clean Wisconsin said in court papers.

Another opponent, power-plant builder Calpine Corp. said Wisconsin Energy's lawyers didn't provide a convincing argument for the Supreme Court to take the case directly -- skipping the traditional appeal route of having the case heard next by the state Court of Appeals.

"If increased costs brought about by a delay resulting from legal proceedings provides a basis for bypass and expedited review, then it is hard to imagine a construction dispute that would not qualify for such review," Calpine said in its filing.

Calpine opposes the project because it has proposed an alternative power source, a natural-gas plant in Fond du Lac. S.C. Johnson and Clean Wisconsin oppose the project because it relies on coal, the most polluting form of electricity generation.

Wisconsin Energy filed papers with the court Tuesday, contending that Flanagan's Nov. 29 decision was based on a misunderstanding of the way the state Public Service Commission arrived at its decision more than a year ago to approve the project.

If not promptly overturned, Flanagan's "erroneous ruling will undercut the ability to meet Wisconsin's future power needs and obstruct the Legislature's intent for efficient and timely approval of power plant development through appropriate deference to the commission's exercise of its delegated authority and expertise," the utility said.

Wisconsin Energy contends it needs to have the case heard on a fast-track by the Supreme Court, rather than the Court of Appeals, because it needs to begin construction of the plant by May to meet a schedule that will permit the first of two coal plants to begin generating electricity in 2009.

But other issues remain unresolved, the opponents said, and those threaten the ability of the company to begin construction as much if not more than the Dane County Court's decision.

The project still awaits a water permit from the state Department of Natural Resources, as well as a permit from the U.S. Army Corps of Engineers for a water intake structure in Lake Michigan to serve the plant.

That permit could be the biggest source of delay for the project, said Calpine spokesman John Flumerfelt, noting that a federal permit would likely be challenged and litigated in the federal court system.

The Supreme Court cannot decide whether to take the case until next week at the earliest. The court isn't in session again until Wednesday, Jan. 5, court spokeswoman Amanda Todd said.