Minimal impact seen on New England power grid if Vermont Yankee shuts down

Small impact on power grid seen from nuke shutdown

MONTPELIER, Vt. — It looks like the lights won’t go out in New England if the Vermont Yankee nuclear plant shuts down in 2012.

That’s the word from a range of experts following the Vermont Senate’s vote on Wednesday to deny the plant a 20-year license extension.

Although Vermont gets about a third of its power from Vermont Yankee, the reactor provides only about 2 percent of New England’s electricity demand, according to Paul Peterson, a senior consultant with Synapse Energy Economics Inc. of Cambridge, Mass. The region currently has a power-generation surplus of 4,000-5,000 megawatts, meaning it could lose up to 16 percent of its generation and not face a power deficit,

“All indications are that the surplus will continue for the next several years,” Peterson said.

Power authorities say however that new transmission lines may be needed in Vermont to avoid overload problems and new power sources are being sought to replace Vermont Yankee.

The New England power grid is run by ISO-New England, an independent system operator based in Holyoke, Mass. It tracks power plants and monitors power flows across the region.

Spokeswoman Ellen Foley said a recently completed “needs assessment” indicated that if Vermont Yankee were to shut down, some new electric line construction might be needed to keep the system running smoothly.

“Looking out as far as 2018, initial findings from the ISO’s assessment reveal potential reliability problems for Vermont if the system were to continue as it is today,” Foley said. “For example, under certain conditions, transmission lines in the state could become overloaded with more electricity than they were designed to carry, which can damage the lines.”

She said shutting down Vermont Yankee could add to power-line problems in neighboring areas as well, including parts of New Hampshire and New York. Foley said it was too early to say what new transmission projects might be needed if Vermont Yankee shuts down.

Vermont Yankee delivers some of its power through contracts with the state’s two largest power companies, Central Vermont Public Service Corp. and Green Mountain Power Corp., which take 286 megawatts of the plant’s 650-megawatt output.

That is slated to decline significantly after 2012, even if the plant were to continue operating, with Vermont Yankee expected to sell more of its power on the regional spot market.

Vermont’s utilities, meanwhile, have been shopping aggressively for new power sources to replace Vermont Yankee. More than a year ago, Green Mountain Power CEO Mary Powell announced her company planned to reduce its reliance on Vermont Yankee and negotiate contracts with wind developers and other renewable sources.

Vermont power companies also have been negotiating with Canada’s Hydro-Quebec to beef up power purchase contracts.

The vote in the state Senate to shut down Vermont Yankee followed reports that the aging nuclear plant was leaking radioactive tritium into groundwater and that its owner, Entergy Corp., mislead state regulators about underground piping at the plant.

Entergy said it will continue its efforts with lawmakers and the public to get the 20-year license renewal for Vermont Yankee.