Monthly wholesale electricity prices and demand in New England, May 2026

Wholesale power prices averaged $49.24 per megawatt-hour (MWh) in the Real-Time Energy Market in May 2026, up 50% compared to the previous year.¹ Day-Ahead Energy Market averages were $45.80/MWh, up 30% from May 2025.  

By the numbers

	May 2026	Percent Change from May 2025	Percent Change from April 2026
Average Real-Time Electricity Price	$49.24 per megawatt hour	+50.3%	+7.7%
Average Natural Gas Price	$2.20 per MMBtu	−13.7%	−5.2%
Peak Demand	19,496 megawatts (MW)	+33.1%	+29.8%
Total Electricity Use	8,548 gigawatt-hours (GWh)	+1.5%	+3.1%

Drivers of wholesale electricity prices

In general, the two main drivers of wholesale electricity prices in New England are consumer demand and the cost of fuel used to produce electricity.

Power plant fuel

Natural gas is the predominant fuel in New England, used to generate 54% of the power produced in 2025 by New England’s power plants. As a result, natural-gas-fired power plants usually set the price of wholesale electricity in the region, and average wholesale electricity prices are closely linked to natural gas prices.

The average natural gas price during May was $2.20 per million British thermal units (MMBtu), which was down 14% from the May 2025 average.² The Mass. index price is a volume-weighted average of trades at four natural gas delivery points in Massachusetts, including two Algonquin points, the Tennessee Gas Pipeline, and the Dracut Interconnect.

Wholesale electricity and natural gas prices

Electricity demand

Demand is driven primarily by weather, as well as economic factors, because changes in weather drive the use of heating and air conditioning equipment. Since air conditioning use is far more widespread than electric heating in New England, weather tends to have a greater impact on electricity use in summer than in winter.

Total demand (or total electricity use) during May 2026 was 8,548 gigawatt-hours (GWh), an increase of 1.5% over May 2025. The average temperature this May was 59 degrees Fahrenheit (F°) in New England, up 1° from the previous May, while the average dew point, a measure of humidity, was 45°F, down 4° from the previous May. These conditions drove an overall increase in heating and cooling needs versus the norm for New England.

Like total demand, peak demand is also correlated with the weather. Consumer demand for electricity peaked for the month on May 20 during the hour from 5:00 to 6:00 p.m., when the temperature in New England was 85°F and the dewpoint was 61°. The May 2025 peak occurred between 6:00 and 7:00 p.m. on May 16, when the temperature was 75°F and the dewpoint was 63°.

Monthly peak demand and total energy use

Resource mix and emissions

The mix of resources used in any given time period depends on price and availability, as well as supplemental resource commitments needed to ensure system stability. Natural-gas-fired generation produced most of the electricity generated within New England in May, with the remainder generated by nuclear, renewables, hydroelectricity, and a fraction from batteries, oil-fired resources, and other resource types.³ The region also received net imports of about 1,261 GWh of electricity from neighboring regions.

May generation in New England, by fuel source

The mix of resources used to produce the region’s electricity is a key driver of carbon dioxide (CO₂) emissions. The ISO estimates these emissions through an analysis that blends data on electricity generation by fuel type with an emissions factor for each fuel that is based on data from the US Environmental Protection Agency.⁴  New England power plants produced an estimated 1.64 million metric tons of CO₂ in May 2026, a 14% decrease from the previous May.

May estimated CO₂ emissions in New England, by fuel source (metric tons)

Estimated CO₂ emissions from natural-gas-fired plants — typically the region’s largest source of power system emissions, due to the significant amount of electricity these resources produce — decreased 16% year over year. These resources accounted for 78% of the power system’s total emissions.

Oil-fired resources produced less than 1% of the total CO₂ emissions in May 2026. Because the region’s wholesale electricity markets select the lowest-priced resources needed to meet demand, oil-fired resources tend to run more frequently when natural gas prices rise, and less frequently when natural gas prices are low.

CO₂ emissions from other resources — mostly refuse and wood — accounted for about 22% of the power system’s estimated CO₂ emissions, a roughly 7% decrease from May 2025.

By the numbers

	May 2026 Estimated Emissions (metric tons)
Natural Gas	1,274,470
Refuse, Wood, Landfill Gas, and Methane	358,872
Oil	5,702

Estimated year-to-date emissions through May 31 increased 7% year over year. The increase was largely driven by a cold snap at the beginning of the year.

High demand, coupled with limited pipeline availability into New England, drove higher natural gas prices, and many generators used oil as a more economical alternative. This resulted in higher emissions from oil-fired generators.

Average annual CO₂  emissions from electric generation in the region have declined significantly in the last decade. The ISO New England Electric Generator Air Emissions Reports provide a more comprehensive analysis of New England electric power generator air emissions and a review of relevant system conditions.

May year-to-date estimated CO₂ emissions in New England, by fuel source (metric tons)

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1. One megawatt (MW) of electricity can serve about 750 to 1,000 average homes in New England. A megawatt-hour (MWh) of electricity can serve about 1,000 homes for one hour. One gigawatt-hour (GWh) can serve about 1 million homes for one hour.

2. A British thermal unit (Btu) provides a uniform standard for comparing the heat value of different fuels. One million British thermal units are shown as MMBtu.

3. Resources that could be included in Other are demand response, hybrid solar/battery, hybrid wind/battery, fuel cells, and geothermal resources.

4. The factors used to estimate CO₂ emissions were updated in October 2025. ISO New England analysts regularly review and refine the methodology used to develop these emissions factors in order to reflect the characteristics of New England’s generating fleet and improve the accuracy of the estimates.

Historical weather data provided by DTN, LLC. Underlying natural gas data furnished by ICE.