ISO-NE expects sufficient summer power supplies

New England should have the necessary resources to meet peak consumer demand for electricity this summer under both typical and extreme weather conditions, according to ISO New England Inc., the operator of the region’s bulk power system and wholesale electricity markets.

Societal changes in response to the COVID-19 pandemic are expected to change consumer demand for electricity during the summer months, but these changes do not pose a reliability threat because the system is designed to handle fluctuations in consumer demand. ISO New England has observed a 3 to 5% decline in consumer demand attributable to the pandemic.

“We expect the pandemic to continue to affect the way consumers use energy throughout the summer, though the exact changes are impossible to predict due to uncertainty regarding social distancing measures and economic activity,” said Vamsi Chadalavada, the ISO’s executive vice president and chief operating officer. “New England’s power system is able to account for and respond to this uncertainty.”

ISO New England prepares short-term forecasts for the summer and winter seasons, taking into account estimated contributions from all resources, including those with and without an obligation through the capacity market to supply electricity; unplanned resource outages; imports from neighboring regions; and resource additions and retirements. These estimates help inform ISO New England’s planning on how to operate the grid during the upcoming peak season.

2020 summer peak demand forecast

This summer, under typical weather conditions, electricity demand is forecasted to peak at 25,125 megawatts (MW). Extreme summer weather, such as an extended heat wave, could push demand up to 27,084 MW.

These forecasts incorporate the demand-reducing effects of more than 3,300 MW of energy efficiency measures, an additional 400 MW reduction from 2019. This decrease is made up of resources that are designed to save electricity across many hours, but cannot change the amount saved in response to instructions from system operators. Examples include the use of energy-efficient appliances and lighting, and advanced cooling and heating technologies.

The forecasts also include a reduction of nearly 800 MW during the peak hour that can be expected from the region’s behind-the-meter solar photovoltaic (PV) installations. Though New England has more than 3,000 MW of solar PV installed, these systems produce their highest output in the early afternoon hours. The increase of solar power in New England has, in effect, pushed the peak hour of grid demand later in the day, when the sun is lower in the sky and production from solar PV systems is also lower. Rather than peaking during the mid-afternoon, as was customary in the summer before PV installations became more widespread, demand for grid power now peaks in the early evening hours.

More than 33,000 MW of capacity is expected to be available to meet New England consumer demand for electricity. ISO New England employs a variety of resources to meet demand: generators that produce electricity, using fuels such as natural gas, nuclear, oil, coal, hydro, biomass, and wind; demand-response resources that reduce their energy use; and power imported into New England from New York and Canada.

Last summer’s demand peak was 24,004 MW and occurred on July 30, 2019. The all-time record for peak demand was set on August 2, 2006, when demand reached 28,130 MW after a prolonged heat wave. In New England, consumer demand for electricity is highest during the summer because of air conditioning use.

Operating procedures to maintain reliability

ISO New England has well-established operating procedures to maintain grid reliability in the event of an unexpected power plant or transmission line outage, an extended heat wave that results in increased consumer demand, fuel supply issues or emissions limitations that affect the amount of electric generation available or a combination of these factors. These procedures include importing emergency power from neighboring regions, calling on power system reserves, and asking businesses and residents to voluntarily conserve energy.