Season on Season

Seasonal Comparison

Nuclear refuels in spring and fall and runs flat through the peaks, so the only honest comparison is the same season in a different year. Pick one market to compare it across years, or several to compare them against each other.

Season

Fall 26 +53 earlier

Markets · click to add or remove

All U.S. PJM MISO ERCOT ISO-NE NYISO CAISO SPP TVA Southern Duke Carolinas SRP FPL Duke Progress BPA Dominion SC

Fall 2026, ISO-NE

Season in progress

Fall 2026 averaged 67 MW off line across ISO-NE, 2.0% of installed nuclear capacity, peaking at 1,243 MW on October 12. 1 refueling outages started in the window, median 4 days. Only 107 days of the season have been reported so far, so treat the comparison as partial.

Average MW off line

2.0% of installed capacity

Season peak

1,243

Oct 12, 2026

vs Fall 2025

███

Individual

vs 3-year average

███

Individual

Refueling outages

median 4 days

Unplanned events

1 reactor trips

Units involved

distinct reactors off line

Energy not produced

172 GWh

over the whole season

The Same Season, Year on Year

ISO-NE

Every line is the same calendar window in a different year, so the curves are directly comparable. The current season is drawn heaviest. Where the lines separate is where a year was genuinely different, not where the calendar moved.

Add 53 more seasons to the comparison Individual · $165/mo

Your plan reaches back to the current season. The record runs to Spring 2000. Most readers do not want to click through the archive a season at a time. The depth is worth having in bulk, to fit a model against, which is what the API and the bulk export are for.

Deeper season history on every chart
The full daily series behind it
Bulk export and API access
Every market, not just the national curve

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Season by Season, ISO-NE

1 season in your window · 53 more on record

Spring seasons in cyan, fall in gold. Fall is normally the heavier of the two: more units refuel into the winter peak than out of it. The hatched bars are seasons outside your history window. They are drawn at a fixed height to show the record exists, not at their real value, so the chart never hints at a figure you have not unlocked. Unlock the full record.

Fall 2026 by Market

heaviest first · click a market to add it to the comparison

Market	Avg MW off	Peak MW	% of fleet	Refuels	Unplanned	vs a year ago
ISO-NE	67	1,243	2.0%	1	1	██	Remove

Season History, ISO-NE

1 of 54 seasons in your window

Season	Avg MW off	Peak MW	Peak on	% of fleet	Refuels	Unplanned	Units
Fall 2026 partial	67	1,243	Oct 12	2.0%	1	1	2
53 earlier seasons back to Spring 2000, and the daily series behind them. Unlock

How to read older seasons. The megawatt columns are built from the daily power record of the units operating today, carried back; the outage counts include units that have since shut down. Across recent seasons those are the same fleet, so the two agree. Go back far enough and the megawatt figures describe today's fleet in an older year, which is the right basis for comparing supply but not for counting what the industry did at the time.

Season history follows the same backward window as the national curve and the ISO breakdown, so there is one rule across the product rather than a special case here. The full record runs to Spring 2000; for model fitting, take it through the API or the bulk export rather than a season at a time.

The record says what happened. What about what is coming? Individual · $165/mo

The forward curve is the same question pointed the other way: a probability band on MW offline out to 18 months, with every published outage date and every projected one behind it.

Probabilistic MW-offline curve, P10 to P90
Every published and projected outage date
The same curve cut by market
Scored daily against what actually happens

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