Resource Mix

New England’s wholesale electricity markets have so far attracted investment in roughly 16,000 megawatts (MW) of new power generation facilities since 1997. The majority is new, relatively low-emitting natural-gas-fired power plants, helping create one of the most efficient fleets of power resources in the country. Investment in new generation ensures that the grid operates reliably and that adequate supply is available to meet demand. Because private firms make this investment and not public utilities, consumers are shielded from the investment risks they had been exposed to before the introduction of competitive markets.

Get an overview of the region’s generating fleet below. Learn more about how the fleet is evolving in Grid in Transition: Opportunities and Challenges.

Sources of Electricity Used in 2017

Here’s the breakdown of the amount of electricity produced by generators in New England and imported from other regions to satisfy all residential, commercial, and industrial customer demand during 2017. This is called Net Energy for Load (NEL).

Note: Data are subject to adjustments. (Last update: 1/17/18.) For the most current information, download the Net Energy and Peak Load by Source spreadsheet in ISO Express.

Fast Stats
  • 350 dispatchable generators
  • About 29,000 MW of generating capability for summer 2018 and 31,000 MW for winter 2018/2019 (seasonal claimed capability)
  • About 45% of regional generation lists natural gas as its primary fuel source, with 11% more listing it as a secondary fuel
  • About 14,800 MW of new generating capacity, mostly wind and natural gas, proposed to be built through 2024, though many projects ultimately withdraw (source: January 29, 2018, ISO Interconnection Queue)
  • 4,600 MW of non-gas-fired generating capacity retired or retiring 2013–2021, with over 5,000 MW from coal- and oil-fired plants at risk of retirement in the coming years
  • Over 2,700 MW of active demand response (DR) and energy efficiency and other passive demand resources are registered in New England (January 2018 DRWG monthly statistics)
  • About 1,500 MW in summer and 1,000 MW in winter of imported electricity are obligated to be available for the region—most from Canadian hydropower
  • Over 130,000 solar power installations totaling about 2,400 MW (nameplate), with most connected “behind the meter”
GWH (a) % of GENERATION % of NEL

(a) GWh stands for gigawatt-hour.

(b) As of January 2016, this chart approximates the amount of generation by individual fuels used by dual-fuel units, such as natural-gas-fired generators that can switch to run on oil and vice versa. Previously, the report attributed generation from such units only to the primary fuel type registered for the unit. The new reporting flows from changes related to the Energy Market Offer Flexibility Project implemented December 2014. See the notes in the Net Energy and Peak Load by Source Report for more details.

(c) “Other” represents resources using a fuel type that does not fall into any of the existing categories. Other may include new technologies or new fuel types that come onto the system but are not yet of sufficient quantity to have their own category.

(d) Tie lines are transmission lines that connect two balancing authority areas. A positive value indicates a net import; a negative value represents a net export.

(e) The energy used to operate pumped storage plants.

(f) Generation
+ net interchange
- pumping load.

Total Generation (b) 102,534 100.0% 84.7%
Gas 49,198 48.0% 40.6%
Nuclear 31,538 30.8% 26.1%
Renewables 10,830 10.6% 8.9%
Wind 3,280 3.2% 2.7%
Refuse 3,165 3.1% 2.6%
Wood 3,014 2.9% 2.5%
Solar 880 0.9% 0.7%
Landfill Gas 447 0.4% 0.4%
Methane 44 0.04% 0.04%
Steam 0 0.0% 0.0%
Hydro 8,572 8.4% 7.1%
Coal 1,684 1.6% 1.4%
Oil 696 0.7% 0.6%
Other (c) 14 0.01% 0.01%
Net Flow over External Ties (d) 20,243   16.7%
Québec 14,401    
New Brunswick 4,306    
New York 1,536    
Pumping Load (e) -1,716   -1.4%
Net Energy for Load (f) 121,061   100.00%

Mix of Supply Resources Has Changed Over Time

The resources making up the region’s installed generating capacity (the megawatt capability of all generating units, demand resources, etc.) have shifted dramatically from nuclear, oil, and coal to natural gas as a result of economic and environmental factors. Similarly, the fuels used to produce New England’s electric energy have shifted.

Despite declines in capacity, nuclear generators typically provide around 30% of the region’s energy and, along with oil- and coal-fired generators, are critical on the coldest winter days when natural gas supply is constrained (as demonstrated on a February day shown below). Coal- and oil-fired resources also make valuable contributions 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 filled the gap. Within a decade, though, the region may have little to no generating capacity left fueled by coal and oil. The region is also at risk of losing more nuclear generators. (See Power Plant Retirements.)

Non-gas-fired resources are critical

Tomorrow’s Energy Mix: Resources on the Way OUT

retiring generators

Several of the region’s oldest generators—and some of its largest—have already ceased operations or plan to exit the markets. About 4,600 MW—an amount equal to about 16% of the region’s current generating capacity—will have shut down between 2013 and 2021 and is likely being replaced primarily by new natural-gas-fired plants and wind resources. Notable exits include:

  • Brayton Point Station (1,535 MW from oil and coal)
  • Salem Harbor Station (749 MW from oil and coal)
  • Vermont Yankee (604 MW from nuclear power)
  • Pilgrim Nuclear Station (677 MW from nuclear power)
  • Norwalk Harbor Station (342 MW from oil)
  • Mount Tom Station (143 MW from coal)
  • Bridgeport Harbor Station (383 MW from coal)

Over 5,000 MW more of New England’s oil and coal capacity is at risk of retirement due to age and infrequent operation in coming years, and uncertainty surrounds the future of 3,300 MW from the region’s remaining nuclear plants. Read about the opportunities and challenges posed by these and other changes to the region’s resource mix.

Total MW Retiring in New England*
Connecticut 737 MW
Maine 37 MW
Massachusetts 3,197 MW
New Hampshire 4 MW
Rhode Island 13 MW
Vermont 640 MW
Total 4,629 MW

Source: ISO New England, Status of Non-Price Retirement Requests; August 18, 2017

* Megawatts (MW) generally based on relevant Forward Capacity Auction (FCA) summer qualified capacity. Total includes full and partial generator retirement requests for Capacity Commitment Period (CCP) 2013–2014 through CCP 2021–2022; does not include retirement requests for demand-response (DR) resources.

Tomorrow’s Energy Mix: Resources on the Way IN

All six New England states have renewable energy standards, which require electricity suppliers to provide customers with increasing percentages of renewable energy to meet state requirements.

State Renewable Portfolio Standards

The New England states are also promoting greenhouse gas (GHG) reductions on a state-by-state basis and at the regional level, through a combination of legislative mandates and aspirational goals.

State Goals Seek Reductions

By examining new generator proposals submitted to the ISO, it’s easy to see how public policy and economics are driving the industry’s choices for tomorrow’s fuel sources. As of January 29, 2018, about 14,800 MW have been proposed in the ISO Generator Interconnection Queue.

by type, by state

Most solar power in New England is connected to local distribution utilities or “behind the meter” directly at retail customer sites. Because such projects do not follow the ISO interconnection process, they aren’t reflected in the ISO Queue numbers above. The ISO must still track solar power’s growth in the region for forecasting and planning purposes, however, since it reduces demand on the grid; the region had over 130,000 solar power installations at the end of 2017. Read more about solar power in New England—its growth, locations, and effects on the system, as well as how the ISO is handling related challenges.

illustration of battery

New types of energy-storage technologies are also emerging in the region. In late 2015, grid-scale battery-storage projects requested interconnection to the regional power system for the first time, with 16 MW achieving commercial operation by late 2016 and more in the ISO Generator Interconnection Queue, as indicated in the chart above. And New England continues to benefit from pumped-storage hydropower—a type of large-scale energy storage; two large facilities built in the 1970s can supply almost 2,000 MW of capacity within 10 minutes. Read “New energy-storage options emerging in New England; ISO-NE publishes primer and makes FERC filing on market participation.”

In addition, the amount of registered demand resources in the region, such as load management, distributed generation, and energy-efficiency (EE) projects, have increased from 100 MW in 2003 to over 2,700 MW in 2018 . This translates into thousands of individual demand assets integrated into the power system. State-funded EE programs are leading the way in this expansion, with investments in EE programs totaling nearly $4.5 billion from 2009 to 2015 and another $1.2 billion annually expected from 2021 to 2026. What’s more, ISO New England has the most demand resources as a percentage of peak demand compared with other grid operators in the country, per a December 2017 report from the Federal Energy Regulatory Commission. We’ve also been a leader in integrating demand-response resources into the wholesale electricity markets and expect to complete full integration June 1, 2018.

While a significant upward trend in renewables and EE is clear, it will be many years before these resources may match the amount of natural gas capacity currently on the system and proposed for development.

New England Energy Efficiency and Power Resources with Significant Growth

Read about solar power in New England—its growth, locations, and effects on the system, as well as how the ISO is handling related challenges.

Learn about how ISO New England is actively pursuing innovations to help create a more efficient, responsive, reliable system that can handle expanded renewable generation and smart grid technology.