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Corporate IESO > Media > News Releases > IESO Releases 2015 Ontario Electricity Data: Sector-Wide Changes Continue to Impact Supply, Demand, Price

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IESO Releases 2015 Ontario Electricity Data: Sector-Wide Changes Continue to Impact Supply, Demand, Price

January 12, 2016

The annual release of electricity data by the IESO points to increased output from renewable sources of supply and continued uptake in electricity conservation programs.


Production by Ontario's nuclear units remained high in 2015, comprising 60 percent of the transmission-connected power generated in Ontario.  Consistent with the rapid growth in wind and solar resources, output from both types of supply increased significantly during the year.  

The table below provides a summary of Ontario's generator output, broken down by fuel type, for the past three years.

Nuclear Hydro Coal Gas/Oil Wind Biofuel Solar/Other
2015 92.3 TWh 36.3 TWh n/a 15.4 TWh 9.0 TWh 0.45 TWh 0.25 TWh
2015 (% of total) 60% 24% n/a 10% 6% <1% <1%
2014 94.9 TWh 37.1 TWh 0.1 TWh 14.8 TWh 6.8 TWh 0.3 TWh 0.0185 TWh
2014 (% of total) 62% 24% <1% 10% 4% <1% <1%
2013 91.1 TWh 36.1 TWh 3.2 TWh 18.2 TWh 5.2 TWh 0.2 TWh n/a
2013 (% of total) 59% 23% 2% 12% 3% <1% n/a

Due to rounding, percentages may not add to 100.

While the table above captures supply connected to the high-voltage transmission system, Ontario is also experiencing rapid growth of smaller scale distribution-connected, or embedded, generation. At the end of 2015, there were nearly 3,000 megawatts (MW) of IESO-contracted embedded generation helping to meet Ontario's electricity needs – an increase of approximately 20 percent from the 2,479 MW of embedded generation available at the end of 2014.


Electricity consumption in Ontario declined in 2015. Total energy withdrawn from the high-voltage transmission system in 2015 reached 137.0 terawatt-hours (TWh), down from 139.8 TWh in 2014 – a two-percent drop that can be attributed to conservation initiatives, increases in embedded generation, mild weather and broader economic shifts.

After 2014, when demand for electricity peaked at 22,774 MW on January 7 during a frigid winter, the province reverted to its normal status as a summer-peaking jurisdiction. Demand for electricity in 2015 reached 22,516 MW on July 28, though the summer was generally characterized by moderate temperatures. Contributing to this relatively low summer peak were increased output from solar units (at the distribution level, where it offsets demand for grid-connected supply) plus ongoing growth in demand management and energy-efficiency measures.


The weighted wholesale price of electricity – the Hourly Ontario Energy Price (HOEP) – for 2015 came in at 2.36 cents/kilowatt-hour (kWh). The estimated 2015 Global Adjustment (GA) rate as at December 31, 2015 was 7.78 cents/kWh. The total cost of power for Class B consumers, representing the combined effect of the HOEP and the GA, was 10.14 cents/kWh.


Ontario is connected to a large network of transmission systems across North America, which supports system reliability and economic efficiency. Imports compete against domestic generation to provide electricity at the best possible price and to support the province's needs during periods of high demand. Ontario also exports electricity when economic and to help maintain system reliability.

Ontario continued to import energy in 2015, with Quebec providing the lion's share. On the export side, the lower Canadian dollar played an important part in the growth of exports to Michigan and New York.

The table below provides a summary of Ontario's electricity imports and exports for 2014 and 2015.

2015 Total Imports 5,763.5 GWh
2015 Total Exports 22,618.0 GWh
2014 Total Imports 4,923.2 GWh
2014 Total Exports 19,073.3 GWh
Change from Previous Year (Imports) +17.1%
Change from Previous Year (Exports) +18.6%


Conservation is a cost-effective and reliable resource that leverages investments that have already been made in existing assets and reduces the need for new electrical infrastructure. Preliminary results for the first nine months of 2015 indicate 489 gigawatt-hours (GWh) of net energy savings attributable to programs delivered by local distribution companies and the IESO.

Other Major Initiatives

The year 2015 was marked by a number of other initiatives at the IESO, including:

  • completion of Ontario's first demand response (DR) auction;
  • selection of participants in the DR pilot;
  • signing of an agreement with Bruce Power to secure an ongoing supply of power from the site and refurbish six nuclear units following two years of negotiations;
  • announcement of successful proponents for the second phase of the IESO's energy storage procurement; and
  • launch of the new six-year Conservation First Framework to support delivery of conservation programs by local distribution companies.

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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