Access documents related to the Operational Impacts of Extreme Weather Events Key Project.
In 2022 and 2023, the ISO worked with the Electric Power Research Institute (EPRI) to conduct a probabilistic energy-security study for the New England region under extreme weather events and developed the Probabilistic Energy Adequacy Tool (PEAT) for the ISO to use to assess operational energy-security risks associated with extreme weather events. In 2024 and 2025, the ISO worked with regional stakeholders to establish a Regional Energy Shortfall Threshold (REST) that establishes an acceptable level of energy shortfall risk.
The ISO will conduct annual processes for running PEAT assessments and comparing against the REST. The risk-trend data identified in these assessments are intended to guide evaluation of whether the possibility of violating the REST requires development of regional solutions to mitigate modeled risks (which could include market designs, infrastructure investments, demand response programs, and price responsiveness by end-use customers) and, if so, when to begin to develop solutions.
This initiative has been a collaborative opportunity for industry leaders and regional stakeholders to learn about how extreme weather events in the future may affect the evolving power system and to prompt thinking about how best to prepare. Weather, particularly changing extremes and range of variability, is a key factor affecting resource (i.e. energy) availability, demand patterns, and related reliability concerns. Extreme weather events in Texas and California have made it apparent that multi-day or longer energy deficiencies have serious consequences to residents and the economy. Energy-security risks in New England are well documented, highlighting the importance of conducting comprehensive energy-security assessments covering a wide range of operating conditions, including low-probability, high-impact reliability risks (tail risks) related to extreme weather.
The Operational Impacts of Extreme Weather Events project is just one of several key projects at the ISO, which continuously undertakes a variety of short- and long-term projects to enhance the region's competitive wholesale electricity markets and ensure reliable operation of the power grid.
