Independent Electricity System Operator (IESO)
Ontario's Independent Electricity System Operator runs the province's high-voltage grid and its wholesale electricity market. On the map, IESO has 443 power plants with 38.9 GW of capacity, nuclear the largest share at 13.6 GW.
Capacity by fuel
443 power plants with 38.9 GW of capacity, planned generators left out.
- Nuclear: 13.6 GW from 5 plants (35%)
- Hydro: 8.6 GW from 151 plants (22%)
- Natural gas: 8.4 GW from 17 plants (21%)
- Wind: 5.4 GW from 92 plants (14%)
- Solar: 1.9 GW from 142 plants (5%)
- Biomass: 672 MW from 34 plants (2%)
- Battery storage: 250 MW from 1 plant (1%)
- Pumped storage: 174 MW from 1 plant (under 1%)
Largest plants
- Darlington: Nuclear, 3.7 GW, Ontario
- Bruce B: Nuclear, 3.4 GW, Ontario
- Bruce A: Nuclear, 3.2 GW, Ontario
- Pickering B: Nuclear, 2.2 GW, Ontario
- Lennox: Natural gas, 2 GW, Ontario
- Sir Adam Beck 2: Hydro, 1.5 GW, Ontario
- Pickering A: Nuclear, 1.1 GW, Ontario
- Robert H Saunders: Hydro, 1 GW, Ontario
- Greenfield Energy Centre: Natural gas, 1 GW, Ontario
- Goreway: Natural gas, 875 MW, Ontario
States and provinces
- Ontario: 443 plants
Sources
Power plants: EIA-860M (US); NRCan NACEI (Canada, Mexico); WRI GPPD (Mexico); OpenStreetMap via Geofabrik (Canada, Mexico gap fill); USGS USWTDB/USPVDB; EPA eGRID; Natural Earth admin-1; HIFLD control areas; location attributes from WorldPop (R2025A), Global Solar Atlas PVOUT, Global Wind Atlas 4, USFS Wildfire Hazard Potential, the USGS National Seismic Hazard Model and the previous publish's lines and substations; water distances from OpenStreetMap via Geofabrik; gas distances and county queue from the previous publish's EIA gas pipelines and LBNL Queued Up requests; nearest city from Natural Earth populated places; cooling degree days from NOAA NCEI nClimDiv county normals; elevation and slope from the Copernicus DEM GLO-30 (ESA, via AWS Open Data); water stress from WRI Aqueduct 4.0; ozone nonattainment from the EPA Green Book; drought from the U.S. Drought Monitor; tribal land from US Census TIGER/Line. License: ODbL (derivative database; EIA content is public domain, NRCan OGL-Canada, WRI GPPD CC BY 4.0; location attributes from WorldPop, Global Solar Atlas, Global Wind Atlas, LBNL Queued Up and WRI Aqueduct CC BY 4.0, USFS, USGS, EIA, NOAA, EPA, US Census and Natural Earth public domain, Copernicus DEM GLO-30 © DLR e.V. and Airbus Defence and Space GmbH, the U.S. Drought Monitor courtesy of NDMC)
ISO and RTO regions: HIFLD Control Areas grouped by EIA-930 reference tables membership; Natural Earth admin-1 provinces for IESO/AESO/HQ; carbon intensity from EPA eGRID (US) and ECCC National Inventory Report (Canada). License: Public domain (EPA eGRID, HIFLD); ECCC figures under the Open Government Licence – Canada