Dive Brief:

• Dominion Energy has petitioned the ISO-New England about the circumstances under which it could shut its Millstone nuclear plant in Connecticut.

• ISO-NE responded in a letter laying out Dominion’s options and noting that the company has current obligations to continue generating until May 31, 2021.

• ISO-NE does, however, offer options under which Dominion could retire Millstone before the 2021 date, including transferring its capacity obligations to another generator.

Dive Insight:

Dominion was not able to move legislation that would have provided benefits for zero emission nuclear power through the Connecticut legislature, so like nuclear operators in other states, the company is talking publicly about shutting the nuclear plant down.

Dominion’s letter to ISO-New England was part of a “strategic assessment” of Millstone’s options. Dominion has said in the past that without payments beyond those available in the ISO's wholesale markets, Millstone could be at risk of losing money.

In the letter, Vamsi Chadalavada, executive vice president of ISO-NE, noted that under its current capacity auction obligation Millstone is committed to run until May 31, 2021. But Dominion is free to exit the obligation by transferring it to a third party.

Chadalavada also reminded Dominion that the ISO has no authority to force Dominion to keep Millstone running, but the company would have to pay hefty fees if the plant were to exit the ISO early.

The company can, however, exit the ISO by filing a de-listing bid in the ISO’s capacity auction. The next opportunity to do that is March 2018, and earliest it could retire under that process would be 2022-23.

De-listing bids are subject to the scrutiny of the ISO. If the grid operator determines a plant is needed for reliability, it can request the plant defer retirement and can pay the owner a special reliability tariff, subject to ISO and federal approval.

Dominion Energy has never said specifically it intends to shut down Millstone and critics say the plant's finances are not that dire.

“The evidence is clear: Millstone is the most profitable nuclear plant in the country and is not shutting down anytime soon,” Matt Fossen, a spokesman for the Stop the Millstone Payout coalition, told CT New Junkie.

A recent MIT study found Millstone to be the most profitable of the nation’s operating nuclear plants.