Maine’s burgeoning solar industry is up in arms, after many developers received emails from Central Maine Power last week indicating that their projects are causing technical problems at substations that could require costly upgrades.

The controversy is erupting as scores of solar developers are building and proposing projects in Maine worth hundreds of millions of dollars.

The unprecedented activity is being spurred by recent state policies and laws aimed at encouraging a rapid shift 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, reduce carbon emissions and prepare for a changing climate, strongly encourages solar development.

But the solar industry says the current momentum is now threatened because CMP’s apparent technical problems could prompt investors and power buyers to hold back.

“This is a major screwup,” Jeremy Payne, executive director of the Maine Renewable Energy Association, told the Portland Press Herald on Wednesday.

Payne said he hosted a call with concerned company executives on Tuesday that had more than 130 people on it.

“I’ve never seen anything like this,” Payne said, adding that his group plans to ask the Maine Public Utilities Commission to open an investigation.

Asked about the situation Wednesday, CMP spokeswoman Catharine Hartnett said the company is doing its best to address “the enormous and rapid growth in new solar projects” on a system that wasn’t designed for them.

Hartnett said CMP has active requests for 2,000 megawatts of capacity in small renewable projects, known collectively as distributed generation. But the current grid is designed to handle a peak load of only 1,700 megawatts, she said.

“While this generation will be helpful to address future load,” Hartnett said, “it also puts a strain on the current distribution system and specifically creates a safety concern.”

CMP is working on solutions to address those concerns and connect distributed generation projects at the least cost, she said.

A TRIGGERING EVENT

At issue is the process by which renewable power projects connect to the electric grid.

Before any project gets built, a utility does what’s known as a system impact study. The analysis ensures the substation and local distribution network can safely and reliably handle the new power.

Any cost to upgrade the system is the responsibility of the developer. Upgrades in Maine typically run between $100,000 and $600,000, developers say. If the price is too high, the project may not be financially feasible.

If a project does move forward, CMP and the developer then sign an “interconnection agreement” to seal the deal. Typically, that’s the end of negotiations.

But something happened last week that developers say is unprecedented.

SunRaise Investments of Portsmouth, New Hampshire, is developing 16 community solar projects in Maine. Five of them – in Gardiner, Waldoboro, China, Belfast and Baldwin – are valued at $40 million overall and are completed. They have signed interconnection agreements, and the company paid $1.4 million last year for needed upgrades identified by CMP’s engineers.

But last Friday, SunRaise received emails from CMP indicating that six of the solar projects had triggered a voltage problem at its substations. The emails said SunRaise would get an updated system impact study soon. It also included a web link to more than 100 impacted substations across CMP’s service area.

SunRaise executives were stunned. The company also works in New Hampshire, Massachusetts, Vermont and California. It depends on accurate impact studies and upgrade costs to develop projects.

“It’s unprecedented for a utility to go back and change the price of upgrades,” said Patrick Jackson, the company’s senior vice president for business development. “If we can’t rely on that, no one would move forward with a project.”

CMP identified the SunRaise solar arrays as the “triggering project” at its substations, meaning that the power generated by the solar farm was responsible for the voltage problems. That alarmed Jackson, who wondered how one of SunRaise’s projects, a relatively small, 1-megawatt rooftop array on a warehouse in Gardiner, could be a trigger.

“That project is the canary in the coal mine,” he said. “It means CMP’s substation and grid are poorly prepared for 21st century uses. It’s proving they aren’t in a position to handle this transition to electrification and decarbonization. And that’s a much bigger problem.”

Those concerns are shared by Bob Cleaves, co-founder of Dirigo Solar LLC in Portland. Dirigo has partnered with the Irish solar company BNRG Renewables and is on track to invest up to $500 million in Maine and create thousands of construction jobs over the next few years.

“This is a titanic event,” Cleaves said. “What does it mean for the solar industry? What does it mean for CMP’s grid management? What is the ripple effect on the investment community, which finances these projects?”

Dirigo has 16 solar projects now planned within CMP’s territory.

“Ten have received notices of possible additional and yet-to-be-quantified costs,” Cleaves said, “notwithstanding signed agreements and material down payments for the upgrades.”

COMMITMENT QUESTIONED

CMP has been criticized in recent years for what renewable energy advocates considered its longstanding opposition to integrating solar into the electric grid. That posture seemed to be changing over the past several months under the direction of David Flanagan. The former CMP head was brought back as executive chairman to help the company update its practices and repair its image with customers. He personally has reached out to solar executives to see how the company can be helpful.

Last year, CMP put together a team of roughly 100 employees and contractors to help solar developers assess the technical requirements for roughly 600 projects that have applied for grid connections. Many of those projects will drop out, for various reasons. But there appeared to be a new urgency under Flanagan to whittle down the years-long backlog in the so-called interconnection queue.

Cleaves isn’t seeing that level of commitment, however, and said CMP’s latest demands are putting future projects at risk.

“These delays are causing Dirigo to likely delay a $10 million investment in Auburn,” Cleaves said, where he said CMP had committed to finishing an impact study by this month.

“Dirigo now learns that the study will not be completed for many months,” he said. “CMP’s stated reason is a lack of resources.”

Hartnett didn’t address concerns about specific projects, but said the company is working with solar developers “to come to a common understanding of the challenges of the pace of development.”

“We are learning and communicating to all stakeholders as quickly as we can to move forward as quickly as we can,” she said. “We remain committed to Maine’s clean energy goals and rapidly expanding the interconnection of distributed solar generation.”