Total Capacity
-- MW
Last updated September 2018

The charts show Ontario's total installed transmission connected generating capacity. This is the theoretical maximum generating capability if every source was able to contribute 100% of their potential to the grid. The amount each produces at any one time depends on outages, availability and market factors.


The combination of all sources to meet day-to-day electricity demand is called the 'supply mix' and changes hour by hour. Ontario relies on a dynamic mix of generation types to power the grid including nuclear, hydro, gas/oil, wind, biofuel and solar.


Embedded generation or distribution connected generation facilities represent nearly 3,546 megawatts (MW) of capacity as of September 2020. This total is made up of a combination of Solar, Wind, Hydro, Natural Gas (CHP), Bio-energy and Natural Gas (SC/CC). Solar generation in particular reduces summer peaks when air conditioning use is at its highest. Producing electricity closer to where it's consumed, embedded generation has the added benefit of relieving congestion along the transmission lines and reducing line losses. Find out more about embedded generation/distribution connected generation capacity IESO - Ontario's Supply Mix.