Power when you need it
The Independent Electricity System Operator (IESO) is the provincial agency responsible for ensuring a reliable, affordable and sustainable electricity supply across the province where and when it is needed.
We match how much electricity we have (supply) with how much electricity we need (demand). We then direct the flow of this power from generators along 34,000 kilometres of transmission lines to local distribution networks serving communities across Ontario.
To do this complex task, the IESO closely monitors the power grid from our control room to make sure that you, your family, neighbours and businesses always have electricity.
As the grid operator for Ontario, the IESO uses this expertise to prepare the system for the future. We forecast electricity demand, evaluate the system’s ability to meet that demand, plan new infrastructure projects, and secure new sources of electricity supply.
We work closely with municipalities, Indigenous communities and other partners to understand local electricity requirements and priorities, and to identify the best options to meet growing electricity needs.
By planning decades ahead, the IESO makes sure that the system will continue to be reliable and affordable in the years to come.
Strength in a diverse supply mix
There are hundreds of electricity generators across Ontario that connect directly to the provincial electricity grid.
On a minute-by-minute basis, the IESO monitors how much electricity is needed and communicates this information to electricity suppliers across the system. In response, generators adjust their output making sure that the system is running reliably and cost-effectively.
Ontario’s grid is also one of the cleanest in the world – almost 84 per cent of our electricity is produced by generators that do not emit greenhouse gases. Our diverse forms of supply – nuclear, hydro, natural gas, wind, solar and others - and robust energy-efficiency programs help to make sure you have reliable, affordable and sustainable electricity.
2024 Energy Output
Key facts about Ontario's electricity system
Ontario's5.4 million residential and business electricity customers...
live in444 municipalities...
and130+ Indigenous communities...
consuming electricity along34,000+ km of transmission lines...
powered by570+ electricity suppliers...
All in a reliable and affordable electricity system, managed by the Independent Electricity System Operator
Energy Efficiency
Electricity planning in Ontario also includes energy efficiency. The IESO offers incentives through Save on Energy to all Ontarians. Our programs can help businesses become more competitive, homeowners save on their electricity use and their bills and, from an electricity planning perspective, reduce demand. On a regional basis, they help reduce strain on the grid through Local Initiatives designed with community needs in mind.
Given the growing importance of energy efficiency in helping support the grid, new Save on Energy programs have been added to include home insulation, heat pumps, smart thermostats, solar panels and more. To learn more about energy efficiency incentives and rebates, visit www.saveonenergy.ca.
Learn more
If you live or work in the GTA, the IESO offers more information about the region’s electricity needs. Learn more about the IESO’s planning process.