Will Illinois utility-scale net electricity generation from nuclear energy for 2026 be above 97.5 TWh?

I could not find Illinois's January–July 2026 nuclear total, which is the key YTD figure. The only 2026 Illinois monthly numbers I found are June and July, from a third-party site. - [2026-10-15] EIA data on Illinois's 2025 nuclear output, as compiled by World Power Monitor from EIA, is 97.7 TWh (97,670 GWh). That is just above the 97.5 TWh strike. 2024 was 99.2 TWh and 2023 was 97.6 TWh. https://worldpowermonitor.com/us/illinois/ - [2026-09-24] EIA Electric Power Monthly (data through July 2026) shows US nuclear year-to-date at 460,063 GWh for 2026, against 453,065 GWh for 2025 (+1.5%). The state-level table was not retrieved. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_01 - [2026-10-01 approx.] Choose Energy, using EIA data, puts Illinois nuclear at 8,449 thousand MWh in June 2026 and 8,610 in July 2026. July 2025 was 8,498, so July was up 1.3% year on year. Illinois was the top nuclear state. https://www.chooseenergy.com/data-center/nuclear-generation-by-state/ - [2026-10-16] The EIA resolution source is still on a monthly cycle. The next Electric Power Monthly, with August data, is due 2026-10-23. The 2025 state profile is due in November 2026. The full-year 2026 state data would come around February–March 2027 in the Electric Power Monthly. EIA's "Historical State Data" page shows annual data through 2025. https://www.eia.gov/electricity/state/illinois/ - [2026-10-14] NukeWorker tracker: Byron 2 is in refueling outage B2R26 (day 17 of 21). Dresden 3 is at 94% power. All other Illinois units (Braidwood 1 and 2, Byron 1, Clinton, Dresden 2, LaSalle 1 and 2) are at 100%. Quad Cities does not appear in the excerpt I retrieved. https://www.nukeworker.com/outages/live-reactor-status/ - [2026-10-14] Remaining 2026 Illinois outage: Byron 2 (about 2026-09-28 to 10-29). Dresden 3 (R29) is scheduled for about 10-26 to 11-19. Allied Power lists Byron 2R26 as 9/28–10/29 and Dresden 3R29 as 10/26–11/19. Westinghouse's wish list shows Byron from 9/28 and Dresden from 10/27. Another tracker shows Byron starting 10/19, which conflicts. https://alliedpwr.com/nuclear-outage/ - [2026-02 to 2026-04] Illinois outages already done in 2026: LaSalle 1 (Feb 9–27), Byron 1 (Mar 2–Apr 1), and Braidwood 2 (starting Apr 20). Dresden 2 and Quad Cities 2 also had spring work. Quad Cities 2 was in refueling from 2026-03-30. Dresden 3 had a maintenance outage starting 2026-04-08. https://www.nukeworker.com/outages/history/full-year-2026/ - [2026-08-06] Constellation's fleet-wide Q2 2026 capacity factor was 93.0%, against 94.8% in Q2 2025. Planned refueling outage days were 86, against 41 a year earlier. Q1 2026 was 92.3%, against 94.1%. Fleet output fell year on year in both quarters (44,160 vs 45,170 GWh in Q2; 44,666 vs 45,582 GWh in Q1). These are fleet-wide figures, not Illinois-only. https://www.sec.gov/Archives/edgar/data/0001868275/000186827526000097/ceg-20260806991.htm - [2026-10-06 approx.] On the Q2 call, Constellation cited higher planned outage days. It also said the Illinois ZEC program ends in May 2027, which is after the 2026 calendar year. https://www.benzinga.com/news/26/10/62272096/full-transcript-constellation-energy-q2-2026-earnings-call - [2026-10-13] Constellation's uprates (first due 2028) do not affect 2026 output. https://www.positivecurrent.com/constellation-uprates-890-mw-7200-construction-jobs/ - [2026-09 approx.] LowCarbonPower, an unofficial aggregator, says Illinois nuclear fell by 1.3 TWh in "2026" (trailing 12 months to June). This is an unverified lead that points to 2026 running below 2025. https://lowcarbonpower.org/region/Illinois - [2026-04-09 to 2026-05-11] NRC status reports confirm the spring outages and that all other Illinois units were at about 100%. https://www.nrc.gov/documents-reports/document-collections/events-reports-associated-with/power-reactor-status-reports/2026/20260409ps BOTTOM LINE: The 2025 baseline (97.67 TWh) sits only about 0.17 TWh above the strike, so the 2026 result depends on outage days and small derates. The evidence on direction is mixed. Constellation's fleet showed lower capacity factors and more outage days in H1 2026, and one aggregator suggests Illinois is running below 2025. Illinois's July 2026 output was up 1.3% year on year, and the US nuclear YTD is up 1.5%. Byron 2 (to about 10-29) and Dresden 3 (about 10-26 to 11-19) outages are still to come in Q4. NOT FOUND: Illinois January–August 2026 nuclear YTD MWh from EIA's state-level table. The Quad Cities 1 outage timing for 2026 (a 2027 outage is listed). The 2026 Illinois outage-day total versus 2025. Any unplanned Illinois outage news from the last 7–14 days beyond the Dresden 3 derate.

- [2026-10-15] EIA data shows Illinois utility-scale nuclear generation of 97.67 TWh in 2025, or 97,670 GWh. The 2025 final annual data were released 9/14/2026. The threshold of 97.5 TWh sits about 0.17 TWh (0.2%) below that figure. https://worldpowermonitor.com/us/illinois/ (EIA-derived); https://www.eia.gov/electricity/data/state/ - [2026-10-15] Illinois annual nuclear generation in TWh, 2013–2025, rounded: 97.1, 97.9, 97.3, 98.6, 97.2, 98.1, 98.7, 100, 97.0, 98.9, 97.6, 99.2, 97.7. https://worldpowermonitor.com/us/illinois/ - 2013–2025 is 13 years, and 8 of them were above 97.5. The years at or below it were 2013 (97.1), 2015 (97.3), 2017 (97.2), 2021 (97.0) and 2023 (97.6, which is above 97.5 only by rounding). 2025 (97.7) was above by a small margin. - Since 2018, 6 of 8 years were above 97.5. The exceptions are 2021 and, marginally, 2023. 2023 may be about 97.55 and needs its exact figure checked. - Year-to-year swings are roughly ±1–3 TWh. The 2026 fleet is the same 11 units, so the threshold is close to the median of recent outcomes. - [2026-10-15] There is a rough odd/even-year pattern in the 2018–2025 data: higher in 2018, 2019, 2020, 2022 and 2024, lower in 2021, 2023 and 2025. It is probably caused by refueling-outage timing across the 11 units, not by any structural driver. https://worldpowermonitor.com/us/illinois/ - [2026-10-14] The 2026 outage record so far (NukeWorker, NRC status reports): - LaSalle 1 refueled Feb 9–27 (19 days). - Byron 1 refueled Mar 2–Apr 1 (31 days). - Quad Cities 2 refueled Mar 30–Apr 23, then had a maintenance outage starting May 9 (NRC status report). - Braidwood 2 refueled Apr 20–May 6 (17 days). - Dresden 3 had an unscheduled outage Apr 8–13 (6 days). - Dresden 2 was manually shut down around Sep 3 after an instrument fault and was still at 0% on Sep 8 (secondary, unofficial source). - Byron 2 was in a refueling outage (B2R26, 21 days) on Oct 14 at day 17, ending about Oct 29. - Dresden 3 had a refueling outage planned for Oct 26–Nov 19. - https://www.nukeworker.com/outages/history/full-year-2026/ ; https://www.nukeworker.com/outages/live-reactor-status/ ; https://www.nrc.gov/documents-reports/document-collections/events-reports-associated-with/power-reactor-status-reports/2026/20260511ps - [2026-10-14] NRC status on Oct 14 showed Clinton, Dresden 2, LaSalle 1 and 2, and Quad Cities 1 and 2 at 100%. Dresden 3 was at 94%. https://www.nrc.gov/documents-reports/document-collections/events-reports-associated-with/power-reactor-status-reports/ps - [2026-10-16] In 2026 Illinois had 5 scheduled refueling outages through Oct 29 (Byron 1, Byron 2, Braidwood 2, LaSalle 1, Quad Cities 2) plus Dresden 3 starting Oct 26. This compares with the 2025 outage pattern, which I could not retrieve. The 2026 outage count and durations are about typical. https://www.nukeworker.com/outages/history/full-year-2026/ - [2026-04-17] Constellation is uprating Byron and Braidwood by about 135–158 MW combined, through turbine replacements done during refueling outages. Some output gain was expected from 2026, with full output by 2029. Byron's first phase is done. A gain of roughly 0.5–1 TWh/yr at full output is plausible, but only part of it applies to 2026. https://www.wifr.com/2026/04/17/byron-nuclear-plant-completes-first-phase-multi-million-dollar-upgrade-project/ ; https://www.world-nuclear-news.org/Articles/Reprieved-Illinois-plants-to-be-uprated - [2026-09] The low-carbon-power tracker (EIA-based, rolling 12 months to June 2026) shows Illinois nuclear down 1.3 TWh in "2026" versus the prior comparison period. The text is auto-generated and ambiguous, so treat it as a weak and unreliable signal that 2026 is running below 2025. https://lowcarbonpower.org/region/Illinois - [2026-09-24] The EIA Electric Power Monthly for July 2026 was released on Sep 24, and the next edition is due Oct 23, 2026. It carries monthly nuclear generation by state, which would give the January–August 2026 year-to-date figure. I could not read that table. https://www.eia.gov/electricity/monthly/ - [2026-10-15] The resolving EIA publication is the one with complete 2026 data. EIA's final 2025 annual state data came out on 9/14/2026, so final 2026 data would arrive around Sep 2027, well after the Feb 28, 2027 close. The Electric Power Monthly with December data is due around late Feb 2027, so it may be the "first publication" with complete data. The market may therefore resolve on preliminary figures. https://www.eia.gov/electricity/data/state/ BOTTOM LINE: The threshold of 97.5 TWh is almost exactly the median of recent outcomes. Since 2018 the result was above it in about 6 of 8 years, and 2025 landed just above at 97.67. Uprate gains point slightly up and a lowcarbonpower.org data series (ambiguous) suggests 2026 YTD is running a bit below 2025. The base rate is therefore close to a coin flip, leaning slightly to Yes, and the year-to-date monthly EIA data would settle it better than the base rate. NOT FOUND: 2026 year-to-date (Jan–Aug) Illinois nuclear MWh from EIA's Electric Power Monthly; exact 2023 and 2025 values to the MWh; any published forecast, EIA STEO state-level estimate or other-venue market for this metric; a 2025 outage-day comparison.

YES means: EIA's first publication with complete January–December 2026 data shows Illinois utility-scale nuclear net generation above 97.5 TWh (97,500,000 MWh). - [2026-09-24] EIA Electric Power Monthly Table 1.1 (fetched) gives US nuclear for Jan–Jul 2026 at 460,063 GWh, against 453,065 GWh in 2025. That is +7.0 TWh, or +1.5%. Monthly 2026 nuclear ran above the same month of 2025 in January (73,251 vs 71,739), May (65,001 vs 62,145) and June (68,786 vs 66,222). February and March were roughly flat to slightly higher or lower. April was lower (57,373 vs 57,893). July was 71,172 vs 70,781. So national nuclear is ahead of 2025 despite the heavier Constellation outage load noted on Aug 6. The state-level table is not in the fetched page. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_01 - [2026-10] The Choose Energy table, which cites EIA data, shows Illinois at 8,449 thousand MWh in June and 8,610 in July 2026. June 2025 is not shown. July is 1.3% above July 2025 (8,498). Illinois is the top nuclear state, at 45% of its in-state generation in July. Nothing in this table points to a structural 2026 shortfall. https://www.chooseenergy.com/data-center/nuclear-generation-by-state/ - [2026-10-15] The NukeWorker full-year outage history (fetched) shows Illinois's completed 2026 refueling outages were short. LaSalle 1 ran 19 days, Byron 1 31 days, Quad Cities 2 25 days and Braidwood 2 17 days. The fleet-wide average completed outage was 28 days. Illinois's three shortest refuelings were well below that average, so Illinois lost little to planned outages in the first half. https://www.nukeworker.com/outages/history/full-year-2026/ - [2026-10-15] The same page lists the only Illinois forced outages of the year as Dresden 3 (Apr 8–13, 6 days) and the Dresden 2 scram (Sep 4–9, 6 days). The Dresden 2 event is the largest unplanned loss, at roughly 0.15 TWh. Dresden 2 had returned to 100% by the Oct 14 NRC status noted by colleagues. Illinois has had no long forced outage in 2026. https://www.nukeworker.com/outages/history/full-year-2026/ - [2026-10-16] Allied Power lists Byron 2R26 as Sep 28–Oct 29 and Dresden 3R29 as Oct 26–Nov 19. The Dresden 3 window is 25 days and overlaps the Byron 2 end by only a few days. A typical Dresden refueling is about 3 weeks. For example, the earlier Dresden 2 outage ran Oct 30–Nov 20. Both outages are known, scheduled and normal, so Q4 carries no unexpected large loss unless they extend. https://alliedpwr.com/nuclear-outage/ - [2026-10-16] Illinois 2026 has no outage that is not already in the record except Dresden 3. Quad Cities 1 and Clinton appear to have no 2026 outage in the NukeWorker list, which I read as inferred from the Gantt listing rather than stated. Dresden 2 also does not appear to have had a 2026 refueling. If so, Illinois had 6 planned refuelings (Byron 1 and 2, Braidwood 2, LaSalle 1, Quad Cities 2, Dresden 3) against 11 units. That is a light-to-normal load for a year in the odd-year low pattern. https://www.nukeworker.com/outages/history/full-year-2026/ - [2026-10-06] ANS reports that the Google–Constellation uprates are "expected to be delivered by 2028", so they add nothing in 2026. https://www.ans.org/news/2026-10-06/article-8467/google-constellation-reach-11unit-uprate-plan-constellation-to-invest-43-billion/ The earlier Braidwood/Byron turbine work is separate. Avpress (about May 2026) says Byron work began in March 2026 and will finish in 2028, and Braidwood work starts next spring. Some gain from the Byron turbine replacements is possible in 2026. https://www.avpress.com/business/constellation-launches-nuclear-plant-upgrades/article_345fdbe1-8fbb-4489-bc33-1e662af73aec.html - [2026-10-07] The 2025 figure of 97,670 GWh is EIA's final annual figure. Wikipedia's Illinois list gives the same number, citing EIA. EIA's EIA-923 page says final 2025 data came out Sept 14, 2026. All data before 2025 are final. https://www.eia.gov/electricity/data/eia923/ The strike is 0.17 TWh below 2025, about 0.17% of output. Matching 2025's capacity factor would clear it. Illinois's nuclear capacity is unchanged at 11 units. https://en.wikipedia.org/wiki/List_of_power_stations_in_Illinois - [2026-09] LowCarbonPower's "-1.3 TWh" for 2026 is a trailing 12-month figure (Jul 2025–Jun 2026). Its history text says nuclear fell 1.5 TWh in 2025, which matches the 99.2 → 97.7 drop. The 2026 line therefore compares a window that includes H2 2025 against a different base. It does not measure calendar-2026 output. https://lowcarbonpower.org/region/Illinois BOTTOM LINE: The Yes path needs Illinois to match 2025's capacity factor, within about 0.2%. US nuclear is up 1.5% year to date through July, Illinois July was up 1.3%, and Illinois's completed 2026 outages were short. Byron 2 and Dresden 3 are the only remaining outages and both are scheduled and normal. Yes therefore needs no unusual event, only no large unplanned loss or extended outage in Nov–Dec. NOT FOUND: Illinois Jan–Aug 2026 state-level nuclear total from EIA. June 2025 Illinois figure. Illinois 2025 outage-day count. Any Constellation statement on Illinois's full-year 2026 output.

YES means: EIA's first publication with complete January–December 2026 data shows Illinois utility-scale nuclear net generation above 97.5 TWh (97,500,000 MWh). - [2026-09-24] The state-level number the colleagues' reports lacked: EIA Electric Power Monthly Table 1.9.B (data through July 2026, preliminary) puts Illinois nuclear year-to-date at 56,484 GWh. The same period in 2025 was 57,633 GWh, so 2026 is down 1,149 GWh (-2.0%). The US total is up 1.5%, so Illinois is lagging the national trend. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_09_b - [2026-10-16] Deadline arithmetic, derived from the table above and the 2025 total of 97,670 GWh. The 2025 Aug–Dec output was about 40,040 GWh (97,670 − 57,633). Illinois needs about 41,016 GWh in Aug–Dec 2026 (97,500 − 56,484) to clear the strike. That is about 2.4% more than the same months of 2025. The shortfall of 1,149 GWh cannot be recovered without a clearly better-than-2025 finish. My own rough calculation says the 11 units (about 11.6 GW) would need roughly a 96% capacity factor over those five months. Caveat: the 2025 YTD column may have been revised, so the 2025 comparison is approximate. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_09_b - [2026-09-09] Dresden 2 (about 0.9 GW) was shut by hand around Sept 3 over an instrument fault and was still at 0% on the Sept 8 NRC report. That is at least 5 days lost in Aug–Dec, or about 0.1 TWh at minimum, which makes the required step-up harder. I did not find a restart date. https://www.autonocion.com/us/illinois-reactor-rods-that-never-moved/ - [2026-10-14] Q4 is not outage-free. Byron 2's refueling runs to about Oct 29 (about 1.1 GW). The colleagues' reports also show Dresden 3's refueling starting Oct 26 and running to about Nov 19, which is about 24 days at about 0.9 GW, or roughly 0.5 TWh. Two refuelings plus the Dresden 2 trip all fall inside the five months that must outperform 2025. I did not see 2025 Q4 outage data for comparison. Source for the two refueling dates: https://alliedpwr.com/nuclear-outage/ - [2026-10-16] The Jun–Jul 2026 monthly figures (8,449 and 8,610 GWh, Choose Energy) imply Jan–May was about 39,425 GWh. That is below the Jan–May 2025 level of about 40,670 GWh once July 2025 is backed out. The deficit therefore comes from the spring outage season, which is already over and cannot be reversed. July's +1.3% year-on-year gain was only about 112 GWh, so it is far too small to close a 1,149 GWh gap. Choose Energy's June 2025 value is not in my sources, so this split is approximate. https://www.chooseenergy.com/data-center/nuclear-generation-by-state/ - [2026-10-16] The ordinary run-rate is not enough either. Even at the July 2026 pace of about 8.6 TWh per month (the best month shown), Aug–Dec would be about 43 TWh before outages. After roughly 0.1 TWh for the Dresden 2 trip, about 0.5 TWh for Byron 2 and about 0.5 TWh for Dresden 3, the total is about 41.5 TWh. That is only marginally above the 41.0 TWh needed. This is a thin margin that depends on every other unit running at about 100% with no further trips. Illinois's Aug–Dec 2025 total of about 40.0 TWh also shows that even a normal late-year pace gives a miss. - [2026-10-16] Resolution technicality: EIA's 2026 final annual data are not due until September 2027, after the 2027-02-28 close. Per the "first EIA publication with complete data" rule, resolution is therefore likely on the Electric Power Monthly with December data, expected in late February 2027 and carrying preliminary numbers. If that release slips past Feb 28, the market has no resolving data by close. Source: https://www.eia.gov/electricity/data/eia923/ - [2026-09-14] Inertia: the +0.2% margin of 2025 over the strike (97.67 vs 97.5) was already razor-thin. 2026 started 2.0% behind that base, so the status quo of "similar to last year" now points to roughly 95.5–96.5 TWh, not 97.5+. The aggregator lowcarbonpower.org also shows nuclear declining in its 2026 period. https://lowcarbonpower.org/region/Illinois - [2026-08-06] Uprates add nothing material. The colleagues' reports show Byron/Braidwood gains are phased in through 2029, and the 2026 YTD deficit already includes whatever was delivered so far. BOTTOM LINE: Through July, Illinois is 1.15 TWh (-2.0%) behind 2025, which itself only cleared the strike by 0.17 TWh. Yes now needs Aug–Dec to beat 2025 by about 2.4% despite the Dresden 2 trip and two Q4 refuelings, so the status quo points to NO. NOT FOUND: Illinois August 2026 data (the Electric Power Monthly is due Oct 23). The Dresden 2 restart date. 2025 Q4 outage-day comparison. Exact 2025 Aug–Dec MWh on a revised basis.