PORTLAND — Despite initial optimism that Casco Bay would be a good location for wind power, a city waterfront project has produced less energy than expected and a project on Peaks Island has been abandoned because there isn’t enough wind.

This comes as the City Council prepares to act on a wind energy ordinance that would govern where and how wind turbines could be installed.

There was significant fanfare when distributor Nelson & Small installed a wind turbine atop DiMillo’s restaurant on Long Wharf. The company installed the turbine free of charge, confident the publicity would be worth the investment.

However, the DiMillo’s turbine has not produced the energy expected.

“It has continued to get remarkable publicity,” said Steve Hayes, a manager for Portland-based Nelson & Small.

The turbine was installed last summer, and Hayes said a technical glitch has kept it from producing the expected 2,000 kilowatts per hour. Instead of fulfilling 20 to 30 percent of DiMillo’s power needs, the turbine is only producing 5 percent.

However, Hayes said hopes the company will be able to resolve the glitch. In the meantime, 15 other companies have expressed interest in installing the roof-top devices.

“Some are hesitating right now, because it’s only a 14-year payback,” Hayes said.

For other devices, like solar panels, the payback in energy savings that cover the cost of the installation is as little as two years.

Like solar panels, maintenance required by roof-top turbines is low, Hayes said, and they are not likely to generate the controversy that can accompany a large propeller-style turbine.

In fact, Hayes said, when the city’s inspector went to check out the DiMillo’s turbine after it was installed, he had to call and ask where it was.

“He couldn’t find it,” Hayes said. “People don’t see it, don’t notice it there.”

The company has conducted tours to show people the DiMillo’s turbine, and nearly every time, the tour leader has to point out the turbine because people can’t see or hear it, he said.

On Peaks Island, meanwhile, residents who utilized technology provided by Efficiency Maine to test wind resources on city-owned conservation land in the middle of the island have determined the wind just isn’t there.

“The test results suggested that at the height we tested and at the location we tested, we didn’t have enough resource,” said Sam Saltonstall, who heads up the Peaks Environmental Action Team.

The group collected data for a year at a height of 100 feet, and the University of Maine analyzed the data. Saltonstall said the location was not ideal in several ways, particularly because it is not the highest point on the island. Also, he said, the turbine would have to be higher than 100 feet to reach the wind speeds necessary to make it worthwhile, something that would disrupt the views of many people on the island.

Saltonstall said the turbine would never have powered island homes. Instead, it would have reduced the amount the city pays for electricity for Peaks Island School and other municipal buildings.

“When we started, we knew the Casco Bay wind resource wasn’t as good as further up the coast, but we thought it was worth testing,” Saltonstall said.

He said now the PEAT group is focusing on helping people insulate and seal their homes to save energy.

On Wednesday, the City Council is scheduled to hold a workshop on a wind energy ordinance that would regulate the installation of turbines in the city.

It contains height restrictions and setback requirements, and would likely prevent any of the large propeller-style turbines from being installed on the peninsula.

Emily Parkhurst can be reached at 781-3661 ext. 125 or eparkhurst@theforecaster.net. Follow her on Twitter: @emilyparkhurst.