Skip Links
Corporate IESO > Media > News Releases > Ontario’s Electricity System Prepared for Hot, Dry Summer Ahead: Independent Electricity System Operator Provides Summer Reliability Assessment

News and Updates

Ontario’s Electricity System Prepared for Hot, Dry Summer Ahead: Independent Electricity System Operator Provides Summer Reliability Assessment

July 5, 2022

In its quarterly assessment of system reliability, the IESO is forecasting adequate generation and transmission availability to meet electricity demand this summer. While warmer and drier weather, increased energy use and ongoing nuclear refurbishments will result in tighter overall system conditions, the IESO has worked with generators and other suppliers to ensure that the system is prepared.

"How and when Ontarians use electricity continues to change – and we’ll see these trends come into play this summer,” said Leonard Kula, the IESO’s Vice-President of Markets and Reliability and Chief Operating Officer. “Economic growth, hybrid work policies and electrification are driving up demand for energy, which will be more pronounced in the summer as air conditioning use ramps up."

"Ontario has adequate energy supplies to meet this demand and we have taken steps to prepare the system for protracted heatwaves and other weather impacts that could arise,” he added.

While stronger hydroelectric output from spring rains has helped improve the supply forecast, ongoing nuclear refurbishments and increasing demand means that system conditions will be tighter than in previous years. As a result, some planned generator maintenance outages will be rescheduled and there may also be an increased reliance on imports from neighbouring jurisdictions to maintain reliability when temperatures rise above 40°C on the humidex.

Energy conservation efforts will also continue to play an important role. Businesses that participate in the Industrial Conservation Initiative are anticipated to reduce their peak energy use on hot days by at least 1,200 megawatts (MW), roughly enough energy to power a city the size of Ottawa.

Residential consumers can also reduce their energy use at peak without compromising comfort. Save on Energy provides energy-saving tips that help customers beat the heat and save money.

Here are some fast facts about summer electricity use in Ontario:

  • Ontario is a summer-peaking province, with air conditioning accounting for one-third of energy use at peak.
  • Overall electricity use is expected to grow 1.7 per cent in 2022, although the peak demand is expected to remain similar to 2021 levels.
  • When the temperature increases one degree above 16°C, electricity demand increases by 150 MW.
  • An estimated 13 per cent of Ontario homes have smart thermostats that enable homeowners to better control home temperatures and reduce energy bills.

The IESO regularly assesses the adequacy and reliability of Ontario's power system. The Reliability Outlook highlights Ontario’s demand forecast, resource adequacy projections, as well as an assessment of operability and the province’s transmission system. The most recent outlook is available on the IESO web site.

About the Independent Electricity System Operator

The IESO operates Ontario’s power grid 24 hours a day, 365 days a year, ensuring Ontarians receive a reliable and cost-effective source of power when and where they need it. It works with sector partners and engages with communities across Ontario to plan and prepare for the province’s electricity needs now and into the future.


IESO Media Relations


< Back to News Releases