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Reliability for Ontario's electricity system remains positive, says latest Outlook

June 21, 2016

The Independent Electricity System Operator's (IESO) latest 18-Month Outlook report forecasts adequate generation and transmission to supply Ontario's electricity demand over the next 18 months to December, 2017. Long-term forecasts also indicate that Ontario will remain adequately supplied into the foreseeable future.

The report, published quarterly by the IESO, predicts that growth in demand from economic expansion and population increase are expected to be offset by the impacts of conservation and embedded generation.

"Local generation, along with increased conservation and demand response, will continue to have a downward impact on demand, despite population and economic growth," said Kim Warren, IESO's Vice–President of Market and System Operations. "This is a continuation of the underlying trend we've seen for some time."

About 1,150 megawatts (MW) of new supply – 650 MW of wind, 300 MW of gas, 100 MW of hydroelectric and 100 MW of solar generation – is expected to be added to the province's transmission grid over the Outlook period. By the end of the period, the amount of grid-connected wind and solar generation is expected to increase to about 4,500 MW and 380 MW, respectively. The embedded wind generation over the same period is expected to increase to about 700 MW. Meanwhile, embedded solar generation is expected to increase to more than 2,000 MW.

As part of its regular review of system operability, the IESO conducts studies to identify areas of operational needs. Results of a recent operability assessment indicated that there is a system need for more regulation (a service that maintains the required grid frequency and power flows on a second-by-second basis), enhanced resource flexibility to balance supply and demand, and additional grid voltage control. These findings reinforce the need for a robust portfolio of resources that contributes to the continued reliability of the grid. The IESO is taking steps to meet these needs.

The IESO regularly assesses the adequacy and reliability of Ontario's power system. The 18-Month Outlook is issued on a quarterly basis, in conjunction with the Ontario Energy Report, which highlights key trends in the energy sector. The 18-Month Outlook can be found here.

About the IESO

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. For more information, please visit

IESO Media Contact:

John Cannella

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