Almost every year since 2007 a new wind energy plant has gone into service in Maine. Last December, New England's biggest-yet joined the mix, spinning 56 turbines from the hills of the Bingham region — about 30 miles east of the Sugarloaf ski resort as the crow flies.

But now after a decade of rapid growth, wind energy in Maine is stalled. No big new wind projects are likely to go live any time soon, and it could cost billions to unlock enough of the state's wind resource — the best in the region — to serve southern New England's thirst for renewable energy.

More Energy Than Maine Needs

The blades at the Bingham wind farm turn a slow waltz atop a series of white, 300-foot pylons that string out across the misty ridgelines.

"It's mostly fiberglass. They have a spar that runs down through the middle as the main beam support, but they just float on the wind," explained Stacey Fitts. He manages the Bingham Wind Plantation and other assets held by Novatus, one of many investors to pick up the pieces after the nation's biggest renewable energy company, Sun Edison, went bankrupt last year.

Wind turbines have proliferated because they serve public policies that require renewable energy be a part of a state's energy mix. And developers have focused on Maine because it's the windiest part of New England.

But Maine already has more renewable energy than it needs. So this renewable energy is serving contracts with customers in Massachusetts and Vermont.

"This is a commodity just like our forest products industry or some of the other native industries to Maine," Fitts said. "Maine has something that's marketable."

Actually, for the first time in a decade, the product isn't so marketable.

Proximity To Demand

"There doesn't seem to be as wide an appetite for some of these new wind farms in northern New England that there was even just a few years ago, and I'm not sure if that's going to change any time soon," said Dan Dolan, executive director of the New England Power Generators Association.

Dolan and many other observers note that Maine wind energy projects were shut out last fall when they bid on a big southern New England clean energy power contract. Solar and wind projects closer to the demand centers were the real winners.

Being close to demand matters, because as of now, there's no more room on Maine's transmission system to bring new wind power from remote locations to market.

"It was not designed with the purpose of integrating large quantities of generation," said Al McBride, director of transmission strategy for ISO New England, the region's grid system operator.

McBride says Maine's part of the system was originally constructed to handle local electricity usage, and to connect Maine with New Hampshire and New Brunswick. But the system has added more than 750 megawatts of wind-generated electric capacity in the state over the last decade. Adding much more, McBride says, would be like crowding an unpaved carriage road with tandem-trailer trucks.

"There's no remaining headroom on the system," he said.

McBride's job includes analyzing what kind of infrastructure investments would add enough headroom to allow the safe and reliable addition of new energy generation. He and ISO New England are analyzing possible solutions and costs now. Some other groups estimate the cost of bringing significant new wind energy from Maine to southern New England at $2 billion and upwards, depending on assumptions about the region's demand over the next eight to 12 years.

The costliness of that added headroom is at least part of why a northern Maine project twice the size of the one in Bingham recently put construction on hold, forcing the abandonment of a contract with two Connecticut utilities. It's part of why, after years of juggling multiple applications for new wind plantations, Maine land use regulators are now handling none.

So while developers consider their next moves, opponents of industrial wind in Maine are taking a tentative breath.

"It's been a good combination to press pause," said Chris O'Neil, a consultant who represents a group called Friends of Maine's Mountains. "But there's still an interest by wind developers to sink steel in the ground."

O'Neil says pressure is on for new wind generators to qualify for a federal tax credit that ends soon. And wind skeptics are on alert after a recent request for proposals by the state of Massachusetts, seeking enough renewable energy to serve hundreds of thousands of Bay State homes.

Industry players in Maine plan to bid, and they are looking to cut costs by integrating clusters of wind and transmission projects — and, they hope, become competitive again for southern New England's renewable energy customers.

This story comes via the New England News Collaborative, and was first published by Maine Public.