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Ontario's Power System

​​​​​​Ontarians use more than 140 million megawatt hours of electricity a year. Ensuring that there is enough energy to meet that demand is an ongoing and highly-complex process, requiring the close co-ordination of all parts of the system. The IESO is at the centre of it all, directing the flow of power across the province and planning for future energy needs. This section provides an overview of Ontario's power system— from the first flick of a light switch to the final statement on the electricity bill —  ​and everything in between.

Ontario's Supply Mix

Image of a Power StationMore than 16,000 megawatts in new and refurbished supply has been added to Ontario's power system over the last ten years, including increased amounts of renewable resources. Read how Ontario's supply mix is changing and what that means to the system. Learn more

Power System Planning

Image of people walking on a city streetThe IESO develops integrated electricity plans to provide sustainable electricity solutions to Ontarians well into the future. These plans examine possibilities for future electricity demand and how it can be met through conservation, generation and transmission options.   Learn more


Smart Grid in Ontario

Image of a Power StationOntario is a leader in smart grids — with smart meters installed in almost every home and small business. Read how smart grids can enable the more efficient use of the electricity system, improve service and give consumers more control over their energy use. Learn more


Image of people walking on a city streetFor more than a decade, Ontario's power system has been managed using a market-based approach — providing greater efficiency and transparency to the system.​ The IESO is working to improve the way it operates the market to increase benefits to consumers. Learn more


Electricity Pricing in Ontario

Image of people walking on a city streetWhat price structure you pay depends on how much you use. From the Regulated Price Plan to the Hourly Ontario Energy Price, here's a primer on electricity price structures in Ontario. Learn more

Knowledge Centre for Business and Industry

Image of street scene with people walkingOrganizations that use more than 250,000 kWh in electricity a year pay the wholesale market price. Here's valuable information about how businesses can use the wholesale price to their advantage, and other information to help these consumers take control of their electricity costs. Learn more