🗺️ Nuclear Share by Region

Nuclear generation as % of total electricity · by RTO/ISO region and state
EIA-923 · EIA Electric Power Monthly · 2025 annual data
18.6%
US national avg
785 TWh
Nuclear generation
4,217 TWh
Total US generation
94 units
Operating reactors
PJM
Largest nuclear region
Illinois
Most nuclear-dependent state
By RTO / ISO Region
Region Nuclear GWe Nuclear TWh/yr Total TWh/yr Nuclear Share # Units Share Key Plants
PJMMid-Atlantic + Midwest 34.2268764 35% 27
Peach Bottom, Salem, Calvert Cliffs, Braidwood, Byron, Dresden, Quad Cities, Limerick
SERCSoutheast + Carolinas 27.1214669 32% 21
Vogtle 1–4, Catawba, McGuire, Oconee, North Anna, Surry, Millstone, Browns Ferry, Sequoyah, Watts Bar
NYISONew York State 5.141150 27% 4
Nine Mile Point 1&2, FitzPatrick, Ginna (Indian Point retired 2021)
ISO-NENew England 4.535130 27% 3
Millstone 2&3, Seabrook (Pilgrim retired 2019)
WECCWest (excl. CAISO) 5.138174 22% 4
Palo Verde 1–3 (3.9 GWe — largest US plant), Comanche Peak 1&2
CAISOCalifornia 2.317228 7% 2
Diablo Canyon 1&2 (license extended to 2045; was scheduled to retire)
MISOMidcontinent 17.8131873 15% 16
Donald Cook, Prairie Island, Monticello, Clinton, Quad Cities (shared w/ PJM), Point Beach
ERCOTTexas 2.419500 4% 2
Comanche Peak 1&2 (Luminant / Vistra) — Texas is 96% gas + renewables
SPPSouthwest Power Pool 1.29113 8% 1
Wolf Creek (Evergy) — single unit, entire region
Most Nuclear-Dependent States (% of in-state generation)
Illinois
54%
11 units · Constellation fleet · Braidwood, Byron, Dresden, Clinton, Quad Cities, LaSalle
South Carolina
52%
4 units · Duke (Catawba 1&2) + Dominion (VC Summer — 1 unit remains)
New Hampshire
47%
1 unit · Seabrook (NextEra) · 1.3 GWe
Connecticut
40%
2 units · Millstone 2&3 (Dominion) · 2.1 GWe
New Jersey
35%
3 units · PSEG (Salem 1&2, Hope Creek) · 3.6 GWe
Pennsylvania
35%
5 units · Peach Bottom 2&3, Limerick 1&2, Three Mile Island 1 (restarting 2028)
Virginia
34%
4 units · Dominion (North Anna 1&2, Surry 1&2)
Georgia
32%
4 units · Southern Co. (Vogtle 1–4) · Vogtle 3&4 online 2023–24
Minnesota
25%
3 units · Xcel Energy (Prairie Island 1&2, Monticello)
Tennessee
24%
7 units · TVA (Browns Ferry 1–3, Sequoyah 1&2, Watts Bar 1&2)
Arizona
23%
3 units · Palo Verde 1–3 (APS) · Largest US plant at 3.9 GWe
North Carolina
22%
5 units · Duke Energy (McGuire 1&2, Oconee 1–3)
US Nuclear Share — Historical Trend (National)
Nuclear % of US Total Generation · 2000–2024
25% 22% 19% 16% 2000 2005 2010 2015 2020 2024 Indian Point closes 2021 Vogtle 3&4 online →

Nuclear share has declined from ~20% (2010) to ~18.6% (2024) as older units retired. The trend reverses if Vogtle full contribution + Palisades restart + Diablo Canyon life extension hold through 2030. Source: EIA Electric Power Monthly Table 6.1.

Demand Implication by Region — U₃O₈ Consumption Estimates
Region Nuclear TWh/yr Implied U₃O₈ lbs/yr % of US Total Demand Grid Dependency Note
PJM 268 13.4M lbs 34% Largest US nuclear region. Constellation fleet. Unit retirement = immediate gas-fill price spike for 65M+ customers.
SERC 214 10.7M lbs 27% Highest per-unit count. Vogtle 3&4 new capacity added 2023–24. Duke and Southern fleet anchors.
MISO 131 6.6M lbs 17% Duane Arnold (Iowa) retired 2020. Monticello life-extended by Xcel — key SLR decision.
WECC 38 1.9M lbs 5% Dominated by Palo Verde (AZ) — largest US plant by output. Diablo Canyon reprieve adds California baseload.
NYISO 41 2.1M lbs 5% Indian Point (2.1 GWe) closure 2021 cost NY ~19% of nuclear. Remaining 4 units now carry full regional load.
ISO-NE 35 1.8M lbs 4% Pilgrim (MA) retired 2019. Millstone carries CT + MA + RI baseload. Grid stress visible every cold snap.
ERCOT + SPP 28 1.4M lbs 4% Texas nuclear = Comanche Peak only. Wolf Creek (KS) sole SPP unit. Both regions heavily gas-dependent.
Methodology & Sources
Regional nuclear share calculated from EIA Electric Power Monthly Table 3.6 (net generation by energy source and census division) and EIA-923 plant-level data aggregated to RTO footprints. RTO boundaries approximate census divisions; plant assignments based on operator interconnection filings (EIA-860). U₃O₈ consumption estimated at 0.0500 lbs per MWh of net nuclear generation (US fleet average, consistent with EIA-858 reported deliveries ÷ EIA-923 generation). State percentages from EIA Electric Power Monthly Table 5.6.b. Historical national trend from EIA Annual Energy Review Table 8.2. Data: 2024 annual (latest available EIA release).

Why this matters: Nuclear share by region determines how exposed each grid is to uranium supply disruption, re-contracting cycle timing, and license cliff risk. PJM and SERC together account for 61% of US nuclear generation — any policy, price, or supply event flows through those two regions first.