Electricity supplies should be sufficient to meet New England consumer demand this winter, but tight system conditions could develop if extreme peak conditions occur.
During extremely cold weather, natural gas pipeline constraints can limit the availability of fuel for natural-gas-fired power plants. Inclement weather can also affect oil and liquefied natural gas deliveries to the region, as well as generation from renewable resources. ISO New England has implemented near-term market and operations changes based on lessons learned from last year’s historic cold snap.
ISO New England has well-established operating procedures to maintain a reliable supply of electricity on the coldest winter days. Should unexpected generator or transmission line outages create tight system conditions, operators can import emergency power from neighboring regions and ask businesses and residents to voluntarily conserve electricity.
Read ISO New England’s winter outlook press release.
ISO New England issues forecasts for electricity supplies and power system conditions ahead of summer, when New Englanders use the most electricity, and winter, when fuel for generators can be constrained. The outlooks take into account many factors that could be boons or challenges to the reliable supply and delivery of electricity, such as weather forecasts, available generation capacity, and possible resource scenarios.
Because of relatively low demand for electricity during these times of the year, the ISO does not release specific seasonal forecasts ahead of spring and fall. Electricity supplies are generally more than sufficient to meet demand, barring extraordinary circumstances. Typical peak demand ranges from 15,000 to 16,900 MW for spring and 15,900 to 17,300 MW for fall, though peaks can be much higher if summer-like weather edges into these seasons.
During periods of mild weather when there’s little need for climate control, the amount of electricity being generated can at times exceed demand, particularly on weekends and during early morning hours. These situations can be dangerous if too much supply leads to excessively high system voltages and frequencies and unscheduled flows of power into neighboring regions.
When generation and external transactions are anticipated to exceed system demand, the ISO first asks generators to voluntarily lower output and then if necessary may order some generators to reduce output or shut down. This process is carefully executed because:
See details on the ISO’s protocol for managing these situations in FAQs: Minimum Generation Emergency.
