Ten years have passed since Maine enacted a landmark wind power law, designed to attract a new energy industry and decrease dependence on fossil fuels.

It worked, for the most part.

Developers have invested $1 billion erecting more than 375 turbines at 17 locations that have a combined generating capacity of 923 megawatts, the measure of electric power equal to 1 million watts. That’s more wind output than in the other New England states combined, making up 20 percent of the power generated in Maine last year, according to federal energy data.

But as the Maine Wind Energy Act enters a second decade, developers say the state is unlikely to see strings of new turbine towers on the horizon, as market forces overtake policy directives. In 2018, only a 22-turbine wind farm in Hancock County and a four-turbine project in Oxford County have active permit applications.

There are several reasons why.

The most immediate factor is that it’s too expensive to build the transmission capacity needed to connect big new projects in Maine to southern New England. Other renewable sources, namely solar, also are becoming cheaper and easier to site. Levels of citizen and political opposition also persist.

Insufficient transmission capacity in Maine has led states with ambitious clean-energy mandates – Massachusetts, Connecticut and Rhode Island – to mostly reject land-based wind in favor of more affordable and practical alternatives, such as ocean wind farms off their coastlines, hydropower from Canada and scattered solar projects that can be built closer to existing wires.

That’s not the impression Mainers might get from the actions and statements by Gov. Paul LePage and other critics. LePage has spent eight years trying to undermine any renewable energy effort that he considers bad for electric rates, and he has found ready allies. They populate the controversial panel LePage set up last winter to study industrial wind’s impact on tourism, such as his former technical adviser on energy, Jim LaBrecque, now a candidate for state Senate.

LaBrecque appears regularly on Bangor radio station WVOM. Recently, he talked about the study panel and accused the wind industry of not revealing its master plan for Maine, because it feared public backlash.

“We don’t know how many mountains they are going to blow up or where those mountains will be,” LaBrecque told listeners on Oct. 10.

LaBrecque’s statements are a reference to the ambitious goals articulated in the wind act, which was championed by former Gov. John Baldacci in 2007. They call for at least 2,000 megawatts of capacity by 2015, and 3,000 megawatts by 2020, including 300 megawatts offshore.

Maine fell short of the 2015 goal by more than half, and the 2020 target isn’t possible. Reaching 8,000 megawatts by 2030 also seems unrealistic.

But a decade later, the specter of a master plan for thousands of turbines dotting the landscape to reach the law’s targets remains a talking point for detractors, to the dismay of advocates who wonder why these numbers still matter.

“These were never numbers that the industry promoted,” said Dave Wilby, a Brunswick-based energy consultant who sat on a task force Baldacci created to advance wind power in 2007.

The megawatt targets were a political aspiration, Wilby and others say. They were envisioned at a time when there were no wind farms in Maine. Politicians were reacting to $4-a-gallon heating oil and an urgency to cut the state’s dependence in imported fuels.

“It did have an effect,” Wilby said. “It was a signal that Maine wanted to encourage this investment, and a lot of it did come.”

THEN AND NOW

The fixation on megawatt goals also is part of a false narrative, according to Matt Kearns, chief development officer at Boston-based Longroad Energy Partners, that private wind companies collaborate on a collective master plan.

“Name another industry that’s expected to lay out a 10-year business plan,” he said. “How many hotels will there be in Portland?”

Kearns was a vice president at First Wind, the now-defunct company that was Maine’s leading wind developer. The design technology has changed so much over the past 10 years, he points out, that trying to estimate future turbine and megawatt numbers is impossible.

For instance: Maine’s first commercial wind farm was built in 2007, on a ridge above a ski area at Mars Hill in Aroostook County. It has an installed capacity of 42 megawatts, with 28 turbines rated at 1.5 megawatts each, on 260-foot-tall towers. At maximum output, it can create enough electricity to power 19,000 homes. That was the state of the art, at the time.

Today, Longroad is trying to win permits for Weaver Wind, a project on small hills in Eastbrook and Osborn, near Ellsworth. It would have a capacity of 72 megawatts, because the standard turbine size has grown to 3.3 megawatts and the towers are 600 feet tall. Weaver will be able to capture more wind and produce more power – enough to run 40,000 homes – with six fewer turbines than Mars Hill.

The two projects also highlight other differences between then and now.

Aroostook County isn’t directly connected to New England’s electric grid. First Wind had to pay New Brunswick Power, the neighboring Canadian utility, $1 million a year to carry the wind farm’s electricity back into Maine. Aroostook County still lacks a direct transmission connection. That has so far made it uneconomic for aspiring mega-projects, such as the 119-turbine Number Nine Wind Farm, to be built and send power south.

By contrast, Weaver Wind would be able to hook into the grid through a nearby, lower-voltage line that has enough capacity.

Siting criteria also have evolved over the decade. The Mars Hill project is too close to some homes, and First Wind had to pay financial settlements in 2013 with homeowners who complained about noise and other issues. Weaver would be located near two existing wind farms and 2 miles from most homes. And while state regulators are studying the impact of the project on birds and bats, it has drawn little opposition from local residents, according to media reports.

WAITING IN THE WINGS

But it’s the cumulative impact of wind farms, not just the turbine count at each project, that keeps the state’s wind power goals relevant today, according to Chris O’Neil, a spokesman for Friends of Maine’s Mountains.

“Knowing that we have 17 projects, we’re starting to notice the cumulative impact of 900 megawatts,” he said. “If we triple that, where are you going to go in Maine without bumping into a windmill?”

O’Neil said the question of how many turbines developers are going to erect, and where, is rhetorical. But it raises awareness of the threat. For now, he said, there’s a lot of public focus on a controversial proposal to import Canadian hydropower to Massachusetts over a line Central Maine Power wants to build through western Maine. That project would preclude wind farms in the western mountains. But if CMP fails to gain approvals, O’Neil said, it might reopen the door for wind over new transmission lines. One example is a pair of wind projects proposed by NextEra Energy in the Chain of Ponds region that would total 133 turbines.

“These big wind projects are just holding their breath,” he said. “They haven’t gone away.”

Big wind projects worth billions of dollars do continue to bid into requests for clean-energy proposals in southern New England, according to Jeremy Payne, executive director of the Maine Renewable Energy Association. They wouldn’t do that without some expectation that buyers eventually will factor in the cost of building new transmission capacity. As a case in point, the developer of Number Nine Wind Farm in Aroostook County is bidding now to supply power to customers in Rhode Island.

Big-capacity proposals remain a long shot, however. The region’s grid operator, ISO-New England, estimates that it could cost $1 million per megawatt to run adequate transmission lines from Aroostook County.

Payne also expects evolving technology to make wind more available and more competitive. Wind farms obviously produce no power when the wind stops blowing, but some newer projects are being designed to use batteries to smooth ups and downs. The NextEra proposals, called Alder Stream Wind and Moose Wind, would incorporate batteries to store energy generated overnight and release it when needed, for up to four hours.

FASTEST-GROWING SECTOR: SOLAR

Even without batteries, wind has become enough of a factor that ISO-New England has taken steps to accommodate its intermittent contributions.

An average wind turbine in Maine runs about 35 percent of the time on an annual basis, ebbing and flowing with the time of day and the seasons. Grid operators now forecast wind production for every hour of the coming week and use computer software to measure wind production every five minutes. They call on fast-start generators, mostly newer natural gas-fired plants, to fill gaps.

While wind has attracted the attention of politicians and activists, solar power may become the fastest-growing part of this generation shift in the near term.

Solar farms can be located closer to existing transmission lines. They are less site-specific than wind, can also be backed up with batteries and are less visible from a distance. Those advantages may dampen public opposition.

A handful of large solar farms have been proposed in Maine and at least one, NextEra’s 77-megawatt project in Farmington, is moving toward approval and a 2019 construction start. A $100 million investment, it would be the largest in New England.