A prolonged cold weather snap or other unusual weather may put strain on Connecticut’s power grid to the point “controlled outages” may be necessary, Eversource reported to towns such as Newtown last month.

While that scenario is unlikely and would require an extended extreme cold snap longer than any cold snap the state has endured in the last few years, town officials such as First Selectman Dan Rosenthal are reminding residents to be prepared for the possibility in the event that it does happen.

“Last year they issued a similar warning but this year they had more emphasis on the warning,” said Rosenthal. “Though I still think it’s more of an outside chance than a reality.”

The outages have become a distant possibility due to increased demand on the grid but no increases in supply or resilience of the grid, according to Eversource. Issues with fuel supplies, particularly natural gas due to the fighting in Ukraine, are also impacting supply.

Director of Health Donna Culbert said people should have a plan in place in case of outages, such as those who work from home or those who rely on medical equipment that requires power.

Rosenthal said that ISO New England (ISO stands for Independent System Operator) has a website with 21 day energy grid forecasts, where the health of the grid is updated weekly, 21 days ahead. ISO New England is the regional transmission organization and operator of the grid for the six-state region including Massachusetts, Connecticut, Vermont, New Hampshire, Maine, and Rhode Island. The forecasts may be found at iso-ne.com/about/what-we-do/in-depth/21-day-forecast.

Town officials such as Rosenthal and Culbert are monitoring the forecasts every week.

“There have been no emergencies forecast,” said Culbert.

Rosenthal said that the town felt compelled to share this information with the public for the sake of transparency, but is not looking to “stoke fear.”

Culbert said that before controlled outages become a necessity, a likely measure asking the public to conserve electricity by reducing consumption would be issued. Both the town and Eversource would warn the public of the need for conservation as well as whether there is a chance of controlled outages.

Rosenthal said that even if a controlled outage does happen, it is likely to be six to eight hours, not long enough for a home to cool to the point it risks damage from freezing. However, people should be cognizant and have a plan in place to stay warm, stay able to work if they're working from home, and stay in a place where any medical equipment they require can run, if necessary.

“I hope most people understand the need for preparedness,” said Culbert.

According to a press release from ISO New England, the six states in their service region should have adequate electricity supplies under mild and moderate weather conditions this winter.

Prolonged periods of very cold weather continue to pose power system reliability risks, but ISO New England will use procedures and plans, including a rolling three-week energy supply forecast, with the goal of mitigating these conditions should they materialize.

“Based on seasonal weather forecasts and information provided by generators about their fuel arrangements, the region’s power system is prepared for mild and moderate weather conditions,” said Gordon van Welie, ISO New England’s president and CEO. “If long periods of severely cold weather develop, we’ll lean on our forecasting tools to identify potential problems early enough to take proactive measures, such as calling for increased fuel deliveries or asking for public conservation.”

The ISO does not anticipate calling for controlled power outages this winter, 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.

Each year, planning for the winter season begins months in advance. ISO New England works with generators to understand their fuel procurement plans, while offering a pre-winter training to discuss market and operational changes. The ISO also consults seasonal weather forecasts.

The National Oceanic and Atmospheric Administration (NOAA) is projecting above-average temperatures in New England this winter, though a warmer-than-average season does not eliminate the threat of prolonged stretches of cold weather. Climate change is making weather more volatile and harder to predict, while stimulating more severe weather. ISO New England also holds pre-winter briefings with the region’s utilities and government officials to discuss their expectations for the season and test emergency communication procedures. This year, ISO hosted a tabletop exercise with these groups to dive deeper into how the region would respond under extreme conditions.

“Preparing for any season requires coordination,” van Welie said. “By working together in advance, ISO, the utilities, the energy industry, and government officials can ensure we’re all on the same page should challenging conditions materialize.”

A rolling 21-day forecast provides visibility and early warning. ISO New England uses sophisticated forecasts to identify potential energy shortfalls while there is time to prevent them or lessen their impact. ISO routinely monitors weather forecasts and energy supplies, including the availability of pipeline natural gas and expected production from wind and behind-the-meter solar resources. In addition to closely monitoring inventories at regional liquefied natural gas storage facilities, ISO surveys oil-, coal-, and natural gas-fired generators to monitor inventories and increase awareness of potential emissions or environmental limitations.

ISO combines this information with a 21-day forecast of consumer demand to assess regional energy supplies.

Results of this assessment are published weekly to the ISO website. By identifying and publicizing possible fuel supply shortfalls weeks in advance, ISO wants to signal to the region’s wholesale energy market participants the need to contract for additional fuel deliveries. The early warning also allows time for coordination among ISO, the region’s utilities, and government officials, especially if public conservation is needed.

Associate Editor Jim Taylor can be reached at jim@thebee.com.