Convergent Energy

Increasingly, power consumers worldwide are drawing their juice from renewable sources like solar, wind, and water power. But those sources have one big drawback: they’re intermittent. When the sun’s not out or the wind’s not blowing, you can’t just turn them on.

But battery storage, like solar power, is getting cheaper and more available every year — and storage batteries, coupled with alternative power sources, are more and more able to shoulder a portion of the daily or seasonal power load. And in Boothbay, Maine, that concept is getting a chance to prove itself in practice, reports the Portland Press-Herald (see: “Grid-feeding battery system of the future humming in Boothbay,” by Tux Turkel).

“The Boothbay project was developed through a partnership led by New York City-based Convergent Energy + Power,” the paper reports. “The pilot program is being run by GridSolar LLC of Portland for the Maine Public Utilities Commission. Last month, Convergent invited utility representatives from around the Northeast to visit Maine and examine the storage system.”

The backup batteries are just one part of a demand-management strategy developed to prevent the state’s power utilities from having to construct major new transmission lines to serve the town of Boothbay and its neighbors, which sit on peninsulas jutting south into Maine’s Casco Bay.

“The GridSolar pilot combines several alternative strategies designed to keep power lines from being overloaded on hot, humid afternoons, when the area is jammed with tourists and air conditioners are cooling hotels, restaurants and shops,” reports the paper. “Thousands of LED light bulbs have been installed to trim overall power demand. Hundreds of solar-electric panels now produce electricity when it’s needed most. Thermal energy storage units that make ice at night are supplementing air conditioning during the day. A diesel generator can be switched on for an added shot of power. And now, the battery bank stands ready. Taken together, these and other measures conserve and produce 1.8 megawatts, the output of a small hydro dam.”

Portland TV Station WCSH-6 has a report (see: “Alternative power project avoids need for new transmission line,” by Don Carrigan). Grid Solar co-founder Richard Silkman told the station that generator and battery backup will only be called into service occasionally for a limited number of hours on a few days of the year. But it’s worth it, says Silkman, to avoid the cost of new transmission lines.

“Silkman said the whole Boothbay pilot project has cost about $6 million to build,” the station reports. “That cost is paid by CMP customers, but he said the new power line would have cost $18 million, so he says the Grid Solar project is actually saving ratepayers money. Silkman also says the Boothbay region was chosen for the pilot project because it is isolated in terms of electricity – meaning there is a single transmission line that feeds the peninsula towns.”