Philip Bartlett, chairman of the Maine Public Utilities Commission, speaks with reporters at the University of Southern Maine in Portland in this July 2019 file photo. The commission plans to investigate grid interconnections following complaints that Central Maine Power would raise connection fees for solar projects. Credit: Troy R. Bennett / BDN

Maine’s energy regulator is planning three related investigations into whether the state’s electric grid can handle new connections from renewable energy and other generation companies, the Maine Public Utilities Commission said Thursday.

The moves come after Central Maine Power told solar project developers last week that they might need to pay much more to connect to the grid, which could delay projects. The utility reversed course after public pressure, but the issue is still gaining traction among the solar community and lawmakers as the state moves to meet clean energy goals.

Gov. Janet Mills asked commission Chair Phil Bartlett on Monday to investigate the matter, saying that she read with dismay reports that more than 100 CMP substations may require costly and unexpected modifications to interconnect hundreds of megawatts of new solar projects across the state. The commission responded almost immediately to the Democratic governor that it would start an investigation.

On Tuesday, executives at the utility told the commission in a letter that “CMP believes lower cost upgrades, or the complete elimination of upgrades, may be possible with further study.”

That touched off a strong response from the Maine Renewable Energy Association and the Coalition for Community Solar, which criticized the third set of interconnecting pricing from the utility. In a joint letter on Wednesday they also asked the commission for an investigation.

“Their apparent inability or unwillingness to be up to the task stands squarely in the path of the state’s efforts to grow its clean energy economy at a moment when our state has suffered greatly due to the global pandemic,” the groups wrote.

On Thursday, the Legislature’s energy committee listened to comments from CMP executives and solar project designers to gather information on the issue.

The commission plans to open one investigation based on the requests by the governor and the two renewable energy groups, said commission spokesperson Susan Faloon. It also will open a separate investigation to examine grid modernization and whether changes are needed to accommodate future distributed resources and loads. A third related case will look into smaller generation protocols to connect to the grid.

“We expect that these cases will take some time,” Faloon said, adding that their timelines are not yet known.