Claiming that importing 1,200 MW of subsidized Canadian hydropower will destroy New England's competitive power markets and make some Maine power plants too expensive to run, a trio of merchant generation companies are seeking to block Central Maine Power Co.'s New England Clean Energy Connect, or NECEC, transmission project.

In a March 15 petition to intervene filed with the Maine Public Utilities Commission, following a March 8 deadline for testimony, natural gas-fired plant owners Calpine Corp. and Dynegy Inc. joined with Bucksport Generation LLC to oppose the application for a certificate of public convenience and necessity for the $950 million power line by Avangrid Inc. subsidiary Central Maine Power.

Selected as an alternative winning bid for a Massachusetts solicitation for cleaner energy, Central Maine Power's proposed 145-mile-long, high-voltage direct current line through Maine is slated to receive a 20-year power supply contract with Massachusetts electric distribution companies if the original winning bid, Eversource Energy's 1,090-MW Northern Pass transmission project, fails to successfully appeal a denial of a siting permit in New Hampshire.

The companies said in their petition that Avangrid's NECEC project would artificially suppress wholesale energy and capacity prices to the point that existing power plants in Maine, including Calpine's 553.5-MW Westbrook Energy Center and Dynegy's 540-MW Maine Independence Station (Casco Bay), would be at risk of retiring prematurely. Bucksport Generation's 243-MW "tri-fueled" natural gas-, diesel- and biomass-fired plant located at the site of the Verso paper mill could also be at risk.

"The forced premature retirement of any existing fossil fuel plant in Maine would directly impact reliability and reduce the diversity of supply, putting Maine at risk should the proposed Canadian hydropower become unavailable," said the filing.

Any benefits of the NECEC transmission project could be offset, the petition warned, if regional grid operator ISO New England is compelled to keep at-risk power plants running through the use of "reliability must run" contracts and other costly out-of-market mechanisms to ensure grid reliability. The transmission project could also impede the development of renewable energy projects in Maine, the companies claimed.

The filing also noted that Hydro-Québec previously acknowledged that the source of the transmission line's hydropower will be from existing dams that currently sell surplus electricity to New York and New England. "In other words, importing 'clean' energy via NECEC may simply result in increased reliance on fossil generation to make up the difference in supply for other markets — and may not reduce overall carbon emissions by a single pound," said the petition.

Central Maine Power, in a March 23 filing, said the merchant generators are seeking to intervene and "restart the clock" on proceedings that are six months into a year-long case. Approving the request to intervene would not only be biased to CMP but would unfairly give the merchant generators another "bite at the apple" as "the opportunity for presenting intervenor testimony has passed, not once, but twice" already.