Monthly wholesale electricity prices and demand in New England, July 2018

Wholesale power and natural gas prices rose in July

Warmer weather brought increased consumer demand for electricity, pushing up the average wholesale power prices for the month of July 2018 in both the Day-Ahead and Real-Time Energy Markets when compared to the previous year. The day-ahead energy price was up 19.2% to $32.89 per megawatt-hour (MWh)* and the real-time energy price rose 26.5% to $33.67/MWh.

July started in the midst of a week-long heat wave, though New England’s power system operated realiably throughout the hot, humid weather.

Drivers of wholesale electricity prices

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

Power plant fuel: Fuel is typically one of the major input costs in producing electricity. Natural gas is the predominant fuel in New England, used to generate 48% of the power produced in 2017 by New England’s power plants, and natural gas-fired power plants usually set the price of wholesale electricity in the region. As a result, average wholesale electricity prices are closely linked to natural gas prices.

The average natural gas price during July was $2.80 per million British thermal units (MMBtu)**. The price rose 13.3% from the July 2017 average Massachusetts natural gas index price of $2.47/MMBtu. 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. The July average natural gas price recorded a 5.5% increase from the June 2018 price of $2.66/MMBtu.

Electricity demand: 

Demand is driven primarily by weather, as well as economic factors. Energy demand during July 2018 rose by 7.6% to 12,277 GWh from 11,412 GWh in July 2017. The average temperature during July was 75˚ Fahrenheit (F) in New England, compared to 71˚F recorded as the average during the previous July. The average dewpoint, a measure of humidity, was 63˚F in July 2018, up from 60˚F in July 2017. There were 169 cooling degree days (CDD)*** during July 2018, significantly higher than the 98 CDD seen in July 2017. The normal number of CDD in July is 120 in New England.

Consumer demand for electricity for the month peaked on July 5 during the hour from 5 to 6 p.m., when the temperature in New England was 89°F and the dewpoint was 71°. Demand reached 24,436 MW, with 15 MW met through reductions by active demand resources****. The July 2018 peak was 3.6% higher than the July 2017 peak of 23,579 MW, set during the hour from 5 to 6 p.m. on July 19, 2017, when the temperature was 88°F and the dewpoint was 63°.

Peak demand is driven by weather, which drives the use of heating and air conditioning equipment. The all-time high winter peak was 22,818 MW, recorded during a cold snap in January 2004 when the temperature was -1°F and the dewpoint was -20°. The all-time peak demand in New England was 28,130 MW, recorded during an August 2006 heat wave, when the temperature was 94°F and the dewpoint was 74°. Air conditioning use is far more widespread than electric heating in New England, so weather tends to have a relatively greater impact on the summer peak than the winter peak.

Fuel mix: 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 and nuclear generation produced 86% of the 10,707 GWh of electric energy generated within New England during July, at about 58% and 28%, respectively. Renewable resources generated about 8.6% of the energy produced within New England, including 5.2% from wood, refuse, and landfill gas; 1.8% from wind; and 1.5% from solar resources. Coal- and oil-fired units produced under 1%, combined, of the energy generated within New England. Hydroelectric resources in New England generated 4.6%. The region also received net imports of about 1,771 GWh of electricity from neighboring regions, and active demand response accounted for 4 GWh of reduced system demand.

July 2018 and Percent Change from July 2017 and June 2018
July 2018 Change from July 2017 Change from June 2018
Average Real-Time 
Electricity Price 
$33.67 +26.5% +29.4%
Average Natural Gas Price 
$2.80 +13.3% +5.5%
Peak Demand 24,436 MW +3.6% +16.3%
Total Electricity Use 12,277 GWh +7.6% +26.2%
Weather-Normalized Use***** 11,629 GWh -0.5% +16.9%
*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 750 to 1,000 homes for one hour. One gigawatt-hour (GWh) can serve about 750,000 to 1 million homes for one hour. **A British thermal unit (Btu) is used to describe the heat value of fuels, providing a uniform standard for comparing different fuels. One million British thermal units are shown as MMBtu. ***A degree day is a measure of heating or cooling. A zero degree day occurs when no heating or cooling is required; as temperatures drop, more heating days are recorded; when temperatures rise, more cooling days are recorded. The base point for measuring degree days is 65 degrees. Each degree of a day’s mean temperature that is above 65 degrees is counted as one cooling degree day, while each degree of a day’s mean temperature that is below 65 degrees is counted as one heating degree day. A day’s mean temperature of 90 degrees equals 25 cooling degree days, while a day’s mean temperature of 45 degrees equals 20 heating degree days. ****Since June 1, 2018, active demand-response resources have been able to participate on an hourly basis in the wholesale electricity markets. These resources reduce demand in real time.*****Weather-normalized demand indicates how much electricity would have been consumed if the weather had been the same as the average weather over the last 20 years.

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


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