Retirements of Non-Gas-Fired Power Plants

More than 4,600 megawatts (MW)—an amount equal to about 16% of the region’s current generating capacity—will have shut down between 2013 and 2021. These coal- and oil-fired and nuclear power plants are likely to be replaced primarily by new wind resources and natural-gas-fired plants. The closures of just two of those resources—Brayton Point Station in May 2017 and Pilgrim Nuclear Power Station by May 2019—removes 2,200 MW of non-gas-fired capacity. Over 5,000 MW of additional oil and coal capacity are at risk for retirement in coming years, and uncertainty surrounds the future of 3,300 MW at the region’s remaining nuclear plants.


With aging non-gas-fired plants closing, New England will need new ways to meet peak demand and make up for natural gas infrastructure constraints

See Status of Nonprice Retirement Requests and Retirement De-List Bids for the most current list of future and historical resource retirements in New England.

power plant retirements

The Economics of Retirement

Several factors are challenging coal- and oil-fired generators’ ability to recover the cost of capital investments to maintain their older plants and ensure performance or invest in new control technologies to meet stringent state and federal environmental requirements.

  • The rising environmental and economic costs associated with oil and coal have made it difficult for older power plants that use these fuels to compete against newer, faster generators that run on cleaner fuel sources, such as natural gas.
  • These older plants can require up to 24 hours to reach full power production, making it difficult for ISO operators to rely on them when system conditions are tight. Their age and lack of regular operation can also sometimes lead to mechanical problems.
  • Oil-fired power plants tend to keep limited fuel supplies on site to avoid the expense of purchasing oil that they may not use. So, even when called to run, they often can’t run for very long. (The Winter Reliability Programs implemented by the ISO over recent winters have helped address this by incentivizing on-site oil storage.)
  • Low wholesale electricity prices over recent years, largely a result of typically low natural gas prices, have also reduced revenues for these resources when they run.

For many coal- and oil-fired resources, the only option is to retire.

retiring generatorsThe region’s nuclear power plants, which for years have provided baseload generation—as well as emission-free electricity—face similar challenges in recouping enough revenue to support long-term operations and the costs of compliance with regulatory requirements. The closure of Vermont Yankee Nuclear Station in late 2014 removed 604 MW from the region, and its impact was seen in higher annual air emissions between 2014 and 2015. (See the 2015 ISO New England Electric Generator Air Emissions Report.)

These retiring resources are likely to be replaced mainly by wind resources and more natural-gas-fired resources, further taxing the region’s already constrained natural gas transportation system.

Generator Retirements Limit the ISO’s Options for Meeting Winter and Peak Demand

On days when natural-gas-fired generators have unconstrained access to low-cost pipeline gas, they usually produce the majority of New England’s electricity. This is in stark comparison to winter, when heating needs claim most of the regional natural gas supply.

Nuclear power typically provides around 30% of the region’s energy. Coal- and oil-fired resources, despite providing only about 3% of the region’s electricity in 2016, can also make valuable contributions on the coldest days of winter, as well as on the hottest days of summer when demand is very high or major resources are unavailable. For example, on the 2016 summer peak day shown below, a nuclear generator was unexpectedly off line and coal- and oil-fired power plants filled the gap. Within a decade, though, the region may have little to no coal- or oil-fired generating capacity left, and is also at risk of losing more nuclear generators.

In its Operational Fuel-Security Analysis, the ISO has sought for the first time to measure the potential effects of increased retirements and other fuel-related variables on the region’s ability to maintain a reliable supply of electricity in future winters.

System Fuel Mix Map

non-gas generators retiring

Will Adding More Renewables Help?

Wind and solar resources can offset some natural gas use, but their help with the fuel-security challenge is limited by still-low levels of regional installation, as well as the timing of their availability. Learn more in Integration of Renewable Resources and Other New Technologies and in the ISO’s Operational Fuel-Security Analysis.

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