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

AUGUSTA, Maine — The utility that serves almost all of southern Maine is telling solar project developers that they may need to pay more to connect to the grid, which could also delay the projects.

Central Maine Power sent emails to the developers of solar power projects last week warning of additional costs and delays because of problems the utility is having connecting the projects to their electric grid, the Portland Press Herald reported on Thursday.

Maine has seen a rush of solar energy development following legislation designed to spur a transition to renewable energy in the state. But the transition depends on the ability of utilities, like CMP, to integrate the projects into the existing electric grid.

In emails sent to developers, the utility said the solar projects were causing voltage problems at substations where the projects connect, the newspaper reported. That’s despite agreements reached between the utility and developers in advance of a project’s construction in which the developers pay to upgrade the infrastructure as needed.

SunRaise Investment, which is working on 16 solar projects in the state, told the newspaper they had already paid $1.4 million to CMP for upgrades last year and were now waiting to hear back about potential additional costs. Patrick Jackson, a senior vice president at SunRaise, told the newspaper it was unprecedented for a utility to revise the cost after the initial agreement.

“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,” Jackson said.

A spokesperson for CMP, Catharine Hartnett, told the newspaper the company is doing its best to respond to the huge demand for solar projects on a grid that wasn’t designed for them.

“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.”