New England is expected to have sufficient resources to meet consumer demand for electricity this summer under typical weather conditions.
Tight supply margins could develop if forecasted peak system conditions associated with above average hot and humid weather occur.
Should unexpected generator or transmission line outages occur, the ISO can call on resources held in reserve, import emergency power from neighboring regions, ask businesses and residents to voluntarily conserve electricity, or implement emergency procedures to stabilize the grid. Climate change has caused weather to become more volatile and less predictable, increasing the potential for system operators to resort to these actions.
Peak demand forecast, typical weather
Peak demand forecast,
above average weather
Available capacity expected
All-time highest summer
peak demand
(set on August 2, 2006)
Weather is a major factor in how much electricity New Englanders need at any given time, especially during the summer months. Mike Fontaine, the ISO’s Supervisor of Operations Forecasting, explains how forecasting the weather plays a key role in the hour-by-hour operation of the regional power grid.
Annual energy use is lower now than it was in the early 2000s, but levels of peak demand—the highest amount of electricity used in a single hour—have not fallen. New England’s power system is planned and operated to serve demand during those peak hours, even if annual use is not historically high.
New England has approximately 7,000 MW of BTM solar PV installed, and these systems produce their highest output in the early afternoon hours. In the summer of 2023, solar panels produced an average of 3,500 to 5,000 MW during the middle of the day. The increase of solar power in New England has effectively 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. Instead of peaking in the mid-afternoon, as was common during summers before widespread solar panel installations, grid demand now peaks in the early evening hours.
| 1 | Implement Power Caution and begin to allow depletion of 30-minute reserves |
| 2 | Declare Energy Emergency Alert (EEA) Level 1 |
| 3 | Request voluntary load curtailment of market participants’ facilities |
| 4 | Implement Power Watch, a notification that additional OP 4 Actions may be taken; if conditions warrant, issue a public appeal for voluntary conservation |
| 5 | Schedule Emergency Energy Transactions and arrange to purchase energy and capacity from other control areas |
| 6 | Implement voltage reductions of 5% of normal operating voltage requiring more than 10 minutes Declare Energy Emergency Alert (EEA) Level 2 |
| 7 | Request resources without a capacity supply obligation to provide energy for reliability purposes |
| 8 | Implement a voltage reduction of 5% of normal operating voltage requiring 10 minutes or less |
| 9 | Request activation of transmission customer generation not contractually available to market participants during a capacity deficiency, and request voluntary load curtailment by large industrial and commercial customers |
| 10 | Implement Power Warning and issue urgent public appeal for voluntary conservation |
| 11 | Request state governors’ support for ISO appeals for conservation |
