Last updated: November 10, 2016


  • Pilgrim nuclear power plant may close as early as 2019.

  • Pilgrim is the only operating nuclear plant in the state and generates 61 percent of the state's low-carbon power.

  • Nuclear closures would exacerbate Massachusetts’ and New England’s dependence on insecure natural gas supplies.

  • A number of climate scientists, conservationists and environmentalists urged the governor and the state legislature to amend the state’s renewable energy mandate to include nuclear.

In August 2016, a new renewable energy mandate was passed and signed into law, requiring 1,600 MW of capacity from wind, more than double the capacity of Pilgrim (685 MW). But because nuclear plants operate at a 90% and higher capacity factor while offshore wind at 40%, the electricity generated from the new wind will be less than Pilgrim's. The new mandate excluded nuclear power and will do nothing to preserve Pilgrim.

A number of climate scientists, conservationists and environmentalists urged the Governor and the Legislature to amend the legislation, and warned that "unless they are amended to support nuclear power as well, they could make the situation worse." In fact, Massachusetts' energy policies put at risk two other nuclear plants in the New England grid, Millstone and Seabrook.

Increasing renewable penetration through mandates will result in a glut of capacity, perpetually falling prices and rising costs which would help to make the largest source of clean electricity, nuclear power, even more uneconomic until it gets displaced by the intermittent renewables and a larger share of natural gas needed to back them up. In fact, it could result in negative prices as has happened in other markets, with system operators desperately trying to shed excess generation when unneeded surges of wind or solar power are threatening to crash the grid. During these crises of overproduction, nuclear plants have to pay to send power to the grid.