Drivers rushing to western Maine ski country or to test their luck at Oxford Casino need to glance quickly to the side of Route 26 to see a vanguard of the clean energy movement sweeping across Maine.

Behind a fence and tree line, 30,000 solar-electric panels are being installed on rows of south-facing metal racks, filling 38 acres of what was once scrubby, cutover woodland.

Over the next few years, hundreds of thousands of similar panels will be scattered across thousands of acres in Maine, including farmland and cut forest.

In an unorganized township in Hancock County, for instance, a recently approved project envisions between 300,000 and 400,000 panels lined up across 495 acres of former timberland that had been cleared for wild blueberry production. The panels’ surface area alone will cover 95 acres, according to the developer’s permit application.

This unprecedented activity is being spurred by recent state policies and laws aimed at encouraging a rapid shift away from oil and gas to renewable electric power for running cars and heating buildings. The state’s new Climate Action Plan, a blueprint for how to electrify Maine’s economy and prepare for a changing climate, strongly encourages solar development.

But despite the urgency around those policies, Maine has no specific rules for where large solar arrays should be sited, as some states do. The decisions are left to developers and landowners, as well as existing state and local permit review processes.

What’s more, converting fields and forest to other uses could undermine competing values articulated in the climate plan. For example, the plan calls for increasing the amount of local food consumed in Maine from 10 percent to 30 percent by 2030. It seeks to triple the acreage of working forest and farmland in conservation, because of their ability to store carbon dioxide and offset greenhouse gas emissions.

At the Oxford solar project, the land wasn’t valuable farm or forest. It’s adjacent to Oxford Plains Speedway and was zoned for a business park that was never built. And it’s barely visible from a busy highway already lined with commercial development.

One of the Oxford land’s biggest attributes is that it’s close to a suitable utility connection, to feed power to the grid. That’s a starting point for siting any solar project.

“When we go look for land, once we know the grid connection, it comes down to economic and environmental concerns, said Nick Mazuroski, a director at BNRG/Dirigo Solar. “They really go hand in hand.”

BNRG/Dirigo Solar, a joint venture of companies based in Portland and Ireland, has 36 active projects in Maine, with 10 under construction. Those projects will have a total output of 296 megawatts, enough to power 50,000 average homes.

The panels will cover a total of 971 acres. They’ll be installed on a range of landscapes: An old landfill in Skowhegan. Blueberry barrens in the town of Hancock. In Auburn, 36,000 panels are going on 45 acres of woods, grass, gravel and wetlands.

In some instances, solar can coexist with other uses. In Rockport, BlueWave Solar will install panels next year on an operating blueberry farm, in an experiment to see if both sun and berries can be harvested successfully. The Boston-based company is working to build 19 projects in Maine that will cover a total of 387 acres.

BlueWave will work with the Rockport grower and the University of Maine to study a 10-acre plot and the impact of the panel arrays on shade and temperature, for instance. Half of the land will be hand-harvested; the other half will use a specially built mechanical harvester.

It’s a small project, roughly 4 megawatts, with enough output for 800 homes. But Alan Robertson, the company’s senior director for commercial and industrial development, said BlueWave has worked with farmers in Massachusetts. It’s exploring other dual-use solar projects in Maine, at a farm that grows pumpkins in Carmel and on grazing fields in Benton.

Another solar developer trying to steer clear of valued real estate has chosen a spent gravel pit in Baldwin and the rooftop of a warehouse in Gardiner. Urban settings such as warehouses and parking garages would seem like obvious alternatives. But Patrick Jackson, co-founder of SunRaise Investments of Portsmouth, New Hampshire, said installation costs are higher on roofs and parking lots. That makes solar less competitive, or forces utility customers to pay more for power.

“There also aren’t enough rooftops and landfills that are feasible,” Jackson said. “You need to put a lot of solar in the ground. So the question then is, where should it go?”

One idea is to put it where energy infrastructure already exists, such as next to a smaller, six-year-old solar array at the Brunswick Landing business campus. But even there, competing values are causing conflict.

Bowdoin College won town approval last month to add 18,000 panels on 20 acres of a 115-acre site it owns. The project will help Bowdoin achieve its sustainability goals. But the land is a rare grassland habitat that has been identified in only four areas of the state, leading to pushback from the Maine Coast Heritage Trust and others.

COMPETING INTERESTS

As more solar goes under contract in Maine, the siting question becomes more complicated – at both ends of the land use spectrum.

On one end, conservation groups are worried about what they call habitat fragmentation. Research has shown that a warming planet is prompting southern wildlife to slowly migrate north. Conservation groups want to establish unbroken, natural highways and habitats to aid this movement and to maintain the region’s biological diversity. But solar farms, which tend to be fenced in for security and safety reasons, can have the cumulative effect of creating a patchwork of roadblocks on the land.

In the absence of specific siting rules, conservation and farmland interests are taking a first swipe at setting up voluntary guidelines for developers to follow.

Maine Audubon, for instance, has put together what it calls a solar siting toolkit, aimed at steering development away from high-value natural resources and agricultural lands. It includes best practices and model siting guidelines. The toolkit features a geographic information system, or GIS, mapping tool that lets the user overlay and zoom in on important features. A user can type in a location and, through a filter, tease out the proximity of high-value plant and animal habitats, farmland soils or gravel pits, or see the distance to a utility substation.

The Nature Conservancy is in the process of using that kind of GIS mapping to help identify the best and worst sites based on habitat fragmentation. The group says large, connected blocks of undeveloped habitat are critical to accommodating species as their ranges shift with a changing climate.

“That’s part of the struggle of how development works,” said Kate Dempsey, the group’s Maine state director. “These are individual decisions, but we’re not as good at permitting at a bigger scale. We’ve got to look at the whole system.”

Other states, including New Jersey and Massachusetts, already are using variations of conservation mapping to guide solar development.

New Jersey uses its tool to categorize areas as preferred, not preferred or indeterminate. Overall, it concluded that 29 percent of the state’s land was preferable for solar installations, mostly in residential and commercial areas.

Massachusetts also is seeking to discourage solar at so-called greenfield sites. It recently tightened up its program that creates incentives for solar developers by further restricting projects on land identified as critical to protecting ecosystems or key wildlife species.

On the other end, solar projects, like any large development, can upset nearby neighbors. In Fairfield, a homeowner objected to a BNRG/Dirigo plan to put 30,000 panels in a farm field across from their yard. The town approved the project last year, which was permitted in that zone.

“We run into it on a local level,” Mazuroski said. “But I’m not getting a sense of a statewide sensitivity (to solar siting.)”

SOLAR VERSUS WIND

It’s too early to say whether large-scale solar development in Maine will bring about the broader public pushback that accompanied the expansion of commercial, land-based wind power in the 2010s. But it’s a cautionary tale.

The Maine Wind Energy Act of 2008 set up an expedited review process that made it easier for developers to site projects in certain areas. It worked. Today, roughly 20 percent of Maine’s electricity is generated by wind, more than any other New England state.

But the view of massive towers on remote ridges, and the sound of whirling blades from projects too close to homes, dampened some of the initial political and public enthusiasm around wind power. In 2018, former Republican Gov. Paul LePage enacted a moratorium on new wind projects. That ban was overturned by Democratic Gov. Janet Mills when she took office a year later.

Wind and solar are inherently different, however, in some key aspects. It’s not unusual for modern wind farms to have tower heights and rotor diameters the length of football fields, with multiple turbines sticking up along ridges.

Solar, by contrast, is low-profile and not as visible from a distance. But compared with wind, it takes up a lot more land.

Mainers are starting to see some so-called utility-scale solar projects rise on the landscape, on 250 acres at the Sanford airport, for instance, and on 490 acres that’s part of a dairy farm in Farmington.

This year, Swift Current Energy will begin work on what’s expected to be the largest project in New England when it goes on line in 2023. At 100 megawatts, the Three River Solar project will have the generation capacity to serve 15,000 homes. The $135 million project will feature up to 400,000 panels clustered in six separate fields.

Three Rivers Solar is located on leased land in Township 16, on the Hancock and Washington county line near Deblois. It’s a rare location in New England for a large clean-energy venture – remote, but next to a big grid connection.

The land is a former forest logged to create blueberry fields but never brought into production. It’s next to three commercial wind farms and near timber harvesting operations. A transmission line runs through the site, so power will be fed into it directly from a new substation.

Swift Current plans to maintain a wooded buffer between the western edge of the project and a branch of the Narraguagus River, which sees fishing and canoeing in the spring. And all-terrain vehicle riders still will be able to traverse the site, through an existing gravel road.

The project also promises several financial benefits, such as 149 full-time-equivalent construction jobs, $4.2 million in total tax payments, $11.5 million in land lease payments, and $4.65 million saved through lower electricity costs for customers.

No opposition was voiced for the project during the permitting process, according to Dave Fowler, Swift Current’s senior director for development. Fowler formerly worked for First Wind, the now-defunct company that built most of Maine’s commercial wind farms. He said he doesn’t expect the same level of public concern with solar.

“Certainly a lot less than for wind,” Fowler said. “It just doesn’t have the visual impact.”

RULES FORTHCOMING

State officials want to make sure residents aren’t put off by the scale and land-use requirements of this next wave of solar.

“We absolutely don’t want to lose public support for solar,” said Hannah Pingree, who heads up the Governor’s Office of Policy Innovation and the Future.

A Democrat, Pingree served in legislative leadership when the Wind Energy Act was enacted with little debate. Then, as now, there was an urgency around the need for clean energy, but not as much appreciation of the details of scale and location.

Pingree envisions a more deliberate, inclusive process today, as set out in the new climate plan. By 2022, the plan says, Maine should develop policies to ensure renewable energy siting is “streamlined and transparent, while seeking to minimize impacts on natural and working lands and engaging key stakeholders.”

Pingree said she expects that process to begin in the new year, led by the Governor’s Energy Office, the Maine Department of Agriculture, Conservation and Forestry and interest groups including the Maine Farmland Trust. That process, she said, eventually could lead to legislation in 2022 to create incentives, regulations or other framework to help guide solar development.

“I think we’re really just at the beginning of the clean energy revolution, so it’s important how we do this,” she said.