For the first time, ISO New England has issued detailed predictions for electricity consumption and peak demand 20 years into the future.
The ISO’s annual Forecast Report of Capacity, Energy, Loads, and Transmission (CELT Report) traditionally has examined a 10-year forecast horizon.
Changes in how the region produces and consumes energy, however, prompted the ISO to develop new methods to produce a forecast that is more robust at both large and small timescales. The information aids not only the ISO’s long-term planning efforts, but also policymakers and participants in the region’s wholesale electricity markets, it said on May 19.
While the CELT Report itself is largely unchanged, an ISO-NE Forecast Data workbook has gotten a makeover.
Tabs within the workbook have been consolidated to reflect data-friendly formatting, setting the stage for further expansions and enhancements. Most significantly, the workbook now includes two decades’ worth of forecast results for New England as a whole and for each of the region’s eight load zones.
Annual use on the rise
The forecast shows significant growth in regional energy use each year over the next two decades, from 117,262 gigawatt-hours in 2025 to 168,789 GWh in 2045.
This is a departure from the trend since 2005, in which energy efficiency and behind-the-meter solar have pushed consumption downward. Annual energy use has averaged about 125,000 GWh over the past 20 years.
Driving the projected demand growth is the electrification of heating and transportation as the New England states maintain policies to reduce carbon dioxide emissions. The ISO expects the states will continue to incentivize heat pumps and electric vehicles, but that adoption of these technologies will occur at a slower pace than was assumed in the 2024 forecast, the grid operator said.
Evolving peak demand
Electrification is also expected to alter the times during which New Englanders use the most electricity. By the mid-2030s, the ISO projects that peak demand will occur during the winter rather than the summer, which has seen higher peaks since the 1990s.
The region’s highest-ever annual peak was 28,130 megawatts (MW) on Aug. 2, 2006. In comparison, the highest winter peak to date was 22,818 MW on Jan. 15, 2004.
While both summer and winter peak demand are expected to grow, winter peaks will grow significantly faster. Assuming normal weather conditions, the summer peak is expected to increase by about 30%, from 24,803 MW in 2025 to 32,021 MW in 2045. The winter peak will essentially double, according to the forecast, reaching 40,278 MW in 2045. Peaks could be higher on a hotter-than-normal summer day or a colder-than-normal winter day.
The timing of daily peaks is also expected to change. As part of its enhanced forecasting methods, the ISO now models demand on an hourly basis throughout the 20-year horizon.
"While today’s peak demand almost always occurs in the early evening, heating electrification is expected to result in morning peaks during winter in the latter half of the 2030s. In the later 2040s, both winter and summer could see peaks around 10 p.m. as overnight electric vehicle charging becomes more of a factor," it said.
