The lattice towers Central Maine Power said it is proposing for its New England Clean Energy Connect hydropower line from Canada to Lewiston. This image, looking northwest from Wilson Hill Road in West Forks Plantation toward the proposed transmission line, also contains a photosimulation of five years of vegetation growth that is 10 feet or less in height. Credit: Courtesy of Central Maine Power

A large solar and wind power company is appealing the Maine Public Utilities Commission’s granting of an important certificate for Central Maine Power’s proposed hydropower corridor from Canada through western Maine.

In a notice to the commission dated May 7, attorneys for NextEra Energy Resources objected to the May 3 order in which the commission granted a certificate of public convenience and necessity to CMP, a key step forward for the project.

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Representatives of NextEra said the regulatory commission should have required CMP to analyze alternatives to the project to mitigate negative environmental effects.

The appeal was made to the Maine Supreme Judicial Court, which will set the schedule to hear the case, according to the commission’s spokesman, Harry Lanphear.

The commission’s three members granted the certificate on April 11, along with their simultaneous approval of a stipulation with more than $250 million in benefits over the 40-year life of the project to local towns on the corridor route. Gov. Janet Mills’ office signed the stipulation along with some environmental groups and other parties.

NextEra, which on its website claims to be the world’s largest operator of wind and solar projects, was a party to the commission’s deliberations on CMP’s request for the certificate.

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In its April 11 deliberations, the three commissioners unanimously approved the certificate, saying the benefits of CMP’s New England Clean Energy Connect project outweigh potential adverse environmental and tourism effects.

The appeal claims that state utility regulators did not require CMP to include in its request for the certificate the results of an independent, third-party investigation into the use of non-transmission alternatives.

The appeal also claims the commission did not consider whether the proposed transmission line is reasonable compared to alternatives.

The appeal also alleges that the commission erred legally in approving the stipulation, which NextEra is claiming was not supported by a broad spectrum of interests.

“We are not surprised that an appeal was filed. Each day that this project is delayed means another $3 million dollars line the pockets of dirty fossil fuel generators,” said Thorn Dickinson, vice president of business development for Avangrid, CMP’s parent company.

“As the most important clean energy project to ever come to Maine, New England Clean Energy Connect is a major change in the status quo of Maine’s energy market, threatening these interests,” he said.