The Independent Electricity System Operator (IESO) works at the heart of Ontario's power system, connecting all participants - generators that produce electricity, transmitters that send it across the province, retailers that buy and sell it, industries and businesses that use it in large quantities and local distribution companies that deliver it to people's homes.
Every five minutes, the IESO forecasts consumption throughout the province and collects the best offers from generators to provide the required amount of electricity. This allows customers to see prices fluctuate based on supply and demand. As a result, they can shift consumption away from peaks in demand to times when the price is lower.
The IESO monitors the system and identifies what is required to maintain reliability in the future, reporting on these recommendations through regular publications. In its quarterly 18-month forecasts of the growth in demand for electricity, the IESO assesses whether there will be adequate generation and transmission facilities. In addition, the IESO prepares the semi-annual Ontario Reliability Outlook, which reports on the progress of interrelated generation, transmission and demand-side projects underway to meet Ontario's reliability requirements.
The IESO co-ordinates emergency preparedness for the province's electricity system and played a key role in managing the restoration of power following the August 2003 blackout.
The IESO continues to work with other stakeholders to evolve the market for the benefit of all. Further enhancements will strengthen the market, enhance reliability and provide Ontarians with greater access to information about their power system.