In this March 9, 2019, file photo, solar panels are seen at a former landfill site next to the local Tremont town office. Credit: Bill Trotter / BDN

Maine’s energy world is in an uproar over a finding by Central Maine Power that it must revise its analysis of costly system upgrades needed to serve a boom in new solar power projects.

Patrick Jackson is co-founder of a company called SunRaise Investments, which has constructed five “community solar” projects in Maine over the last year. The company was required to commission a CMP analysis of what upgrades would be needed to make sure the distribution system and substations could safely handle the new electricity load.

SunRaise paid for the studies and the upgrades CMP said were needed was $1 million worth of upgrades. But last Friday, CMP told SunRaise it had identified a voltage issue that could arise if its project and others around the state go into operation without additional substation upgrades.

“Now CMP is saying they made a mistake and that we are going to have to pay for upgrades and they don’t know how much it’s going to cost, or how long it’ll take,” Jackson said. “So it’s either an error on their part or negligence to be bringing this up now.”

Dozens of solar developers in Maine got the same message from CMP, involving more than 100 substations. That’s upended the financial plans of an unknown number of projects already constructed or in the pipeline.

CMP spokesperson Catharine Hartnett said it’s too simplistic to say that CMP did or did not make a mistake. New incentives aimed at “decarbonizing” Maine’s economy triggered a surge in interconnection requests that will have an unprecedented, cumulative effect on voltage, she said.

“We just have a system that over 100 years has been developed very traditionally, and we’ve now had 11 months to try to completely transform it. We need to put the necessary work and careful analysis into making sure it’s done the right way,” Hartnett said.

But one solar power developer, Robert Cleaves of Dirigo Solar, said his company started asking CMP about upgrade needs back in 2015. And he was one of several critics who say CMP has taken its eye off Maine’s energy needs while it focuses on building a new electricity corridor to serve a contract with Massachusetts consumers.

“Apparently they had enough time to connect Canadian hydro with Massachusetts ratepayers but not enough time to connect Maine ratepayers with Maine solar,” Cleaves said in an email.

Developers, lawmakers and environmental groups are calling on CMP’s shareholders to pay any added upgrade costs, and for utility regulators to investigate. Some, including Rep. Seth Berry, co-chairman of the Legislature’s utilities committee, say the issue already has harmed Maine’s reputation as a reliable place to develop renewable energy — and endangered the state’s ambitious climate agenda.

The events are also raising questions about whether current rules for how interconnection costs are paid for are outdated, and don’t take into account the kind of infrastructure changes needed for multiplying “distributed generation” resources such as solar and wind — and whether ratepayers should shoulder some of the costs. Regulators and lawmakers can be expected to examine that issue this winter.

In a statement to Maine Public, Gov. Janet Mills’ energy director, Dan Burgess, said CMP’s actions were cause for concern.

“We are aware of CMP’s recent notifications and share serious concerns about their circumstances and timeliness,” Burgess said. “We intend to engage with CMP to determine what their plans are to address and resolve these issues in a manner that allows projects now underway to securely move forward. “

This article appears through a media partnership with Maine Public.