A fledgling Cincinnati energy company is looking at the Scioto River as a potential source of green power for at least 3,000 homes.

But the idea of turbines and transmission lines at Griggs Reservoir already has opponents, including environmentalists who have been fighting plans for a boathouse at a city-owned park. They don't like the hydroelectric proposal, either.

"It's a contest between green recreation vs. green profits, and the integrity of our parkland is at risk," Alex Silbajoris, chairman of Friends of the Scioto River, wrote recently to the group's members.

Alan Skelly, the chief executive officer of Ohio Power and Light, said the two can coexist.

"When people think of hydro, they think of something big and massive and interfering," he said. "It doesn't have to be that way."

Skelly, whose self-described "alternative-energy, clean-power company" started operations in May 2008, is seeking permission from the Federal Energy Regulatory Commission to study the possibility of hydroelectric operations at Griggs.

Hydroelectric power is produced when water is diverted through a turbine. The mechanical energy created is converted by a generator into electricity.

Federal approval to study the idea at Griggs would be a first, tentative step. Skelly's company and an adviser on the project, Free Flow Power of Gloucester, Mass., would look at the design of the dam, the flow of water in the reservoir and river, and other data to determine whether a hydroelectric project would be possible and profitable.

Other federal agencies would weigh in -- the Interior Department already has raised endangered-species concerns -- and city government would have a say as well.

The administration of Columbus Mayor Michael B. Coleman, which won City Council approval for the Griggs boathouse last month, has "no plans to develop or allow" hydroelectric projects at Griggs, according to a Public Utilities spokeswoman.

Studies for federal approval would take two or three years, Skelly said. He also has asked federal regulators for permission to study similar projects at nine state-owned dams along the Muskingum River in Morgan, Muskingum and Washington counties in southeastern Ohio.

At Griggs, on Columbus' Northwest Side, backers envision building an underwater intake structure into the reservoir side of the dam's western edge. The most visible parts of the project would be a 2,500-square-foot building to house the turbines and generators, a smaller substation on shore and an 1,100-foot overhead transmission line.

Skelly compared his plans to a city-run hydroelectric plant at the dam of O'Shaughnessy Reservoir, 10 miles upstream on the Scioto River. People don't even know it's there, he said.

The Griggs project would have a capacity of 4 megawatts, which is enough to power at least 3,000 homes, according to calculations used by the National Hydropower Association.

O'Shaughnessy's plant has a 5-megawatt capacity.

It rarely operates at that level, though, said Laura Young Mohr, a spokeswoman for the Columbus Department of Public Utilities. The O'Shaughnessy plant, which opened in 1987, needs repairs and hasn't operated consistently for three years, she said.

Even at capacity, according to Mohr, the O'Shaughnessy plant has been a "minor player" for the city's electric utility, which serves 14,000 customers. It was built mostly with federal money through an initiative that followed a 1979 spike in oil prices.

rvitale@dispatch.com