Generation
EIA-923 through Jul 2026The same ISO-NE plants made 0.9% less power than a year earlier. Wind added 612 GWh and nuclear fell 827 GWh. Clean power is 38% of its output, down 6 points since 2019.
How ISO-NE got here
Share of net generation each yearClean power 44% in 2019, 38% in 2025. Hover a year for its mix.
Fuel by fuel
Share is 2025; Jan–Jul compares the same plantsWho makes ISO-NE’s power
2025, 111 TWhEach block is a plant. Hover to see it, click to open its page.
Each block is one plant, sized by its 2025 output; the lighter block holds the smaller plants. Pumped storage, which nets negative, is left out.
This year against last
20262025Running total, same plants, each on its own scaleBiggest gains
CPV Towantic+795 GWh2.7 TWh → 3.5Kleen Energy Systems+657 GWh1.5 TWh → 2.2Vineyard Wind 1+564 GWhfrom zeroGranite Ridge+416 GWh1.7 TWh → 2.1Biggest drops
Seabrook−1.0 TWh6.3 TWh → 5.3ANP Bellingham Energy Pro…−708 GWh2.0 TWh → 1.3ANP Blackstone Energy Pro…−621 GWh1.9 TWh → 1.2Fore River−560 GWh1.7 TWh → 1.1New this year
1 plant, 800 MW, made 564 GWh by July.
Battery discharge
GWh a month2026 months are provisional: monthly reporters only. Plants that report once a year appear when the 2026 file is final.
CO₂ intensity
lb per MWh540 lb/MWh in 2025, up 4% since 2020. The seven ISOs together: 767.
EIA-923: 2019–2025 final; Jan–Jul 2026 counts plants that report monthly (about 78% of ISO-NE’s output last year) and compares them with the same plants in 2025. CO₂ from 2020: EPA CAMPD, or EIA-923 fuel use × EPA emission factors where CAMPD misses a plant or covers it in part. Sources