For nearly eight years, the largest solar array in Minnesota has been an Xcel Energy facility in Chisago County that can power about 20,000 homes.

Soon, that lonely giant will be eclipsed.

Solar developers have proposed 16 colossal projects that would cover thousands of acres of rural Minnesota with glass and aluminum panels to capture energy from the sun.

Many are in the early stages of permitting, and others have significant obstacles. The projects nevertheless represent an unprecedented solar gold rush in a state that has largely relied on wind farms to make the transition to carbon-free energy.

In 2023, solar made up about 3% of electricity generated in a state that's far from the Sun Belt. That number could more than quadruple by 2035, which would make solar the third largest share of power, behind wind and nuclear, according to one projection by the Minnesota Department of Commerce.

Private developers say there's a confluence of factors driving the trend, such as federal tax credits that make mega projects cheaper. One huge draw is increasing demand from local electric utilities that are retiring coal plants to hit corporate goals as well as Minnesota's target of having a 100% carbon-free grid by 2040.

"Minnesota continues to be a market that's going to need a lot of renewable energy," said Beth Soholt, executive director of Clean Grid Alliance, a St. Paul-based trade group for wind, solar and battery developers.

Projects in the pipeline

So far this year, six developers have filed the initial application for permits from the Minnesota Public Utilities Commission (PUC) for major solar projects, and a seventh company told the PUC it plans to seek permits soon.

Each of those solar farms would be capable of producing at least 100 megawatts of electricity, as much as the Chisago County array. Several are far larger. That includes the Iron Pine Solar project in Kettle River Township under development by Massachusetts-based Swift Current Energy, which would serve roughly 45,000 homes after building 2,200 acres of solar panels, an array that would be almost the size of White Bear Lake.

Those projects alone would be enough to significantly boost solar in the state. But they will join at least nine major solar projects approved by the PUC since 2021, though developers haven't started construction on most yet.

Xcel is developing the most notable of the bunch in three stages on the grounds of its soon-to-be-decommissioned coal plant in Sherburne County. At 710 megawatts, the Sherco project will be one of the biggest solar farms in the U.S.

Demand, economics spark a boom

Scott Groux is lead developer for the Birch Coulee project, a solar farm in Renville County proposed by Virginia-based AES Corporation. AES filed an initial permit application with the PUC in July.

Groux said several factors are making solar a better business proposition, including tax credits from the federal Inflation Reduction Act, new power lines under development and Minnesota's 2040 deadline for an energy transition away from fossil fuels.

"100% carbon free, that creates a demand for these kind of projects," Groux said. "The cost of projects going down, the IRA tax credits that are available, these make these projects more feasible."

Minnesota's largest utilities all have plans to build or buy large-scale solar before 2040. Xcel alone has proposed obtaining 1,500 megawatts on its Upper Midwest system by 2033.

"The big player in the state of Minnesota is Xcel," said Scott Wentzell, associate director of development at EDF Renewables North America, which is hoping to build a solar project in Dodge County.

Wentzell said large corporate and industrial customers like data centers are also "aggressively pursuing renewable energy contracts."

Still, high demand for renewable power isn't new, and not all projects make it to the finish line. Many developers had solar plans delayed or scuttled several years ago due to inflation, supply chain problems, a tariff dispute and other factors.

Solar supply chains have recovered more completely from the COVID-19 slowdown than wind, said Pete Wyckoff, an assistant commissioner at Commerce who works to land federal money for clean energy projects.

Yet limitations of the power grid are still slowing solar projects.

The nonprofit Midcontinent Independent System Operator (MISO), which runs the grid in 15 states, must study if transmission infrastructure can handle electricity from each proposal and what upgrades the project developer might need to pay for. There's a long line of projects that want to connect to a grid that's already overtaxed.

The Elk Creek Solar project in Rock County has been delayed for years as Bloomington-based National Grid Renewables waits for a connection agreement, said regulatory adviser Betsy Engelking.

EDF is hoping to start construction on Byron Solar in 2026 after getting permits last May, held up by MISO delays, according to project developer Cody Dierks.

MISO has proposed that utilities across the Upper Midwest build a massive new portfolio of power lines to open up more grid space, but those will take years to permit and build.

Solar 'catching up' to wind

The majority of Minnesota's current solar comes from small-scale arrays, including rooftop systems and the community solar program, which gives Xcel customers a bill credit when they subscribe to a shared array. Xcel expects to add more than 1,000 megawatts of smaller solar arrays by 2030, primarily from community solar gardens. Recent legislative action to revamp and limit community solar, and other constraints in the program, have prompted some developers to eye much larger projects, however, Engelking said.

Wind farms generated about 25% of electricity in Minnesota last year. Wind energy is more prominent in large part because wind is abundant and local utilities are more familiar with the technology and comfortable with its economics.

But Xcel and others have said they can't depend too heavily on wind energy because the wind isn't always blowing. "As you're moving towards a more carbon-free system, it's good to have both resources to balance each other out a bit," said Sydnie Lieb, an assistant commissioner at Commerce who scrutinizes projects at the PUC.

If eventually approved and built — which is not a certainty — the 16 large-scale solar projects would boost supply by more than 2,800 megawatts.

"Solar is starting off way behind," Wyckoff said. "But solar is catching up."