Over the past few years, electric consumption has been declining in New England even as the population and economy have grown. This is due in large part to energy efficiency (EE) gains, which have dramatically reduced the amount of electricity consumed in the region and are projected to do so even more in the future.

Declines in peak demand

The hour of highest electricity demand in New England determines the region’s infrastructure needs. The system is built to ensure it can reliably supply electricity during that hour, which usually occurs on a hot summer weekday.

For the first time ever, ISO New England (the region’s electric grid operator) is predicting a decline in peak demand over the next ten years, mostly due to projected gains in EE and on-site solar generation. Known as the 90/10 peak summer demand forecast, this projection models electric needs during a once-in-ten-years hot weather event and serves as the basis for regional system reliability planning.

The green line represents the ISO peak demand forecast, which factors in solar and energy efficiency.

The 2018 forecast also includes improvements that help it more accurately reflect recent history. Predicted winter peaks (the highest hour of use in the winter) have shifted downward, and projected needs in 2024 are nearly 700 megawatts lower than in last year’s forecast. This is equivalent to the power produced by the retiring Pilgrim Nuclear Power Station in Massachusetts.

Acadia Center looks forward to seeing these revised winter figures incorporated into the updated modeling of ISO’s fuel security study. The initial fuel security study asserted shortages could occur under severely stressed system conditions and sparked calls for new pipelines to carry additional natural gas into the region to fuel power plants. The new forecast should result in significant changes to those predictions.

Beneficial to ratepayers

Since the electric grid is designed and built to meet needs on the peak hour, increases in energy efficiency reduce the need for expensive new construction, which would be paid for by utility customers if built.

Crucial for the future

ISO projects that by 2020, energy efficiency will reduce demand on peak days by more than all of the region’s nuclear power plants combined can supply. By 2027, energy efficiency is projected to reduce the amount of electricity we need to generate by more than 22%.

These figures not only highlight the benefits of the region’s past and planned efficiency, but also give insight into what could be accomplished with more efficiency. Lagging states can continue to expand their efforts, and efficiency improvements could be better targeted at summer and winter peaks if avoided infrastructure costs are more accurately calculated.


  • Jamie Howland leads Acadia’s Climate & Energy Analysis (CLEAN) Center and its Energy Efficiency and Demand Side Initiative. A Connecticut native, Jamie is based in the Hartford office and has extensive experience in energy efficiency and energy markets.