ISO-NE outlines power grid preparedness for winter season

New England should have sufficient resources to meet the peak demand for electricity this winter, according to ISO New England, operator of the region’s electric grid.

Weather is the largest driver of energy use and resource availability in New England, and ISO New England utilizes a rolling three-week energy supply forecast, incorporating a variety of factors to provide an early warning to the region should energy supplies become constrained.

“Seeing what’s coming is crucial to navigating any potential power system challenges, and our 21-day energy supply forecast is an operational tool that serves this very purpose,” said Gordon van Welie, president and CEO of ISO New England. “It gives us situational awareness on energy adequacy over the operating horizon, allowing us to identify potential energy shortfalls while there’s still time to prevent them or lessen their impact.”

This winter the ISO does not anticipate calling for controlled power outages, and would resort to this drastic step only to prevent a collapse of the power system that would take days or weeks to repair. In the event controlled power outages are needed, the ISO would coordinate this action with local utilities, which would then take the necessary actions to lower electricity demand in their areas.

Projected winter electricity needs and weather forecasting

Winter electricity demand is estimated to peak at 20,269 megawatts (MW) during average conditions and 21,032 MW under colder than normal temperatures, a modest increase of 1.3% from last year’s forecasts. New England’s all-time winter peak demand reached 22,818 MW in January 2004. For context, one megawatt (MW) of electricity can serve about 750 to 1,000 average homes in New England. 

ISO New England closely monitors seasonal weather forecasts. The National Oceanic and Atmospheric Administration (NOAA) is projecting above-normal temperatures in New England this winter, with near-normal precipitation for central and northern New England. While an El Niño weather pattern may suggest warmer temperatures overall this winter, it does not preclude the chance of multiple stretches of cold outbreaks that could stress the region’s power system.

A rolling 21-day forecast provides a narrative of system conditions

For the past four years, ISO New England has published a comprehensive energy supply outlook that offers a rolling three-week analysis of anticipated power system conditions. The forecast involves collecting data on various factors like weather, availability of pipeline natural gas, and expected production from wind and solar resources.

The goal of the forecast is to provide an early warning of potential energy shortfalls that could impact reliable operation of the regional power grid if stored fuels such as liquefied natural gas (LNG) run low, especially during periods when the natural gas pipeline system may be constrained. The advantage of this forecast is that it allows for resource owners to take stock of their resource fuel supplies, reschedule maintenance, or arrange for additional fuel deliveries when possible.

The forecasts are published weekly from December through March to the ISO website.

Conservation requests are a tool in managing possible energy shortfalls

ISO New England’s system operators have multiple tools in case of emergencies, including importing additional power from neighboring regions, using power system reserves, and asking businesses and residents to voluntarily conserve electricity. Only in severe situations, if conservation efforts fail to balance electricity supply and demand, would controlled power outages be considered.

During prolonged periods of extreme cold, ISO New England anticipates that generators would use stored fuels like oil and LNG to operate around the clock. Conservation requests during these periods would aim to extend the fuel supplies until warmer weather or additional deliveries of fuel arrive.

Inventoried Energy Program in place

This winter will mark the first year of the Inventoried Energy Program, a two-year program designed to provide incremental compensation to certain resources that maintain inventoried energy during cold periods when energy security is most stressed. ISO New England has seen strong participation in this program from resources entering the winter.

2023-2024 winter outlook by the numbers 

• Winter peak forecast: 20,269 MW under normal weather conditions; 21,032 MW under below-average temperatures
• Last winter’s demand peaked at 19,529 MW on February 3, 2023, when temperatures averaged 4°F
• The all-time winter peak demand is 22,818 MW, set on January 15, 2004, during a cold snap
• Resources with a Forward Capacity Market (FCM) capacity supply obligation to be available: 31,846 MW
• Total resources, including both FCM obligations and capability without FCM obligations: 33,374 MW (a generator’s maximum possible output may be greater than its FCM obligation)
• All-time peak demand: 28,130 MW, on August 2, 2006

For more information, visit www.iso-ne.com/winter.