Graphs show variations in electricity imports, exports

This is the latest installment in a series highlighting data visualizations created by ISO New England to help explain different aspects of the region’s bulk electric system.

The electricity New Englanders rely on doesn’t all come from within the region’s borders. Similarly, electricity produced here doesn’t all stay here.

In 2025, New England imported 18,405 gigawatt-hours (GWh) of electricity and exported 10,237 GWh. That works out to a net interchange of 8,168 GWh, or about 7% of the total electricity consumed in the region throughout the year.

Imports and exports are constantly changing. Their volume at any given time depends on agreements between producers and distributors of electricity, prices in the competitive energy markets, and reliability constraints among New England and its neighboring regions.

Trends in imports and exports are illustrated in ISO New England’s System and Market Operations Report, a detailed overview of information about the regional power grid. The report is presented to members of the New England Power Pool at monthly Participants Committee meetings, and each month’s slide deck is posted publicly on the ISO-NE website.

One slide in the report includes charts breaking down imports and exports on a daily and monthly basis. Imports are shown in green on the positive portion of both charts, while exports are shown in orange on the negative portion. Net interchange (labeled “net tie,” in purple) may be positive or negative depending on whether imports or exports are greater during a given period.¹ New England is only rarely a net exporter of energy. Usually the region imports significantly more than it exports.

These charts only tell part of the story. The next slide in the System and Market Operations Report tells more of it, breaking down imports and exports over seven external interfaces.

Each interface is made up of one or more tie lines connecting New England’s power grid to neighboring regions. Northeastern Maine connects to its neighboring Canadian province via the New Brunswick interface (NB, in purple). New England has three interfaces with Québec: Phase 2 (HQ-Ph2, blue), Highgate (HQ HG, green), and the recently added New England Clean Energy Connect (NECEC, yellow). And there are three interfaces with New York: Northern AC (NY-NAC, orange), Northport-Norwalk Harbor Cable (NY-NNC, gray), and Cross Sound Cable (NY-CSC, red).

ISO Express and the ISO to Go mobile app provide real-time data on imports and exports over external interfaces, as well as on their associated wholesale prices.

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1. The charts do not reflect unscheduled flows that may result from unexpected system events. The values shown may differ from the real-time telemetered information presented on ISO Express. ↩︎