The IESO manages the province's power system so that Ontarians receive power when and where they need it. It plans and prepares for future electricity needs, and works with its partners to guide conservation efforts. A not-for-profit entity established by the Government of Ontario, IESO fees and licences to operate are set by the Ontario Energy Board.

Electricity Data Fast Facts

Installed Capacity 37,044 MW (transmission-connected)
Source: 18-Month Outlook released September 2018
Record Summer Peak 27,005 MW (August 1, 2006)
Record Winter Peak 24,979 MW (December 20, 2004)

Ontario's peak energy use is typically in the summer months when people use air conditioners to beat the heat. Peaks also take place in the winter when the weather is especially cold. Weather has the biggest influence on electricity demand.
Consumers Served 4.9 million 
Transmission Lines 30,000 km
Ontario Import Capability 4,500-5,200 MW
IESO Wholesale Market $17 billion in financial transactions per year
Average Weighted Wholesale Market Price (2017) 1.58¢/kWh
Global Adjustment Class B Rate (2017) 9.97¢/kWh
Total Annual Energy Consumed (2017) 132.1 TWh
Conservation Results 2016 In 2016, Ontarians achieved 1,267 gigawatts (GWh), or 1.267 TWh of energy savings ? for a combined total of 2,810 GWh, or 2.81 TWh, from 2015 and 2016, persisting to 2020.
1 Gigawatt hour (GWh) = 1 million kWh
1 Terawatt hour (TWh) = 1,000 GWh

Energy Output by Fuel Type 2006 vs 2017

Energy Output by Fuel Type - 2006-2017

Notes: Most solar facilities are connected to distribution systems, not the transmission system.Due to rounding, percentages may not add to 100.

What is 1 kWh? infographic

What is 1 kWh?

A cyclist exerts an equivalent of 1 kWh of electricity when biking from London to Guelph. See more at www.1kwh.ca.