Skip Links
Corporate IESO > Media > Year-End Data > IESO Releases 2005 Generation and Consumption Figures


In the IESO's Media Centre, reporters will find timely and relevant information about the IESO, Ontario's power system and the wholesale electricity market. For media inquiries, please contact 416.506.2823 or

Visit the Contact web page for other inquiries.

IESO Releases 2005 Generation and Consumption Figures

The drought-like conditions in parts of Ontario last summer contributed to a drop in the output from Ontario's hydroelectric facilities in 2005 from the previous year, reported the Independent Electricity System Operator (IESO).

The portion of Ontario's electricity production from hydroelectric generators decreased to 22 per cent last year, or 34 terawatt hours (TWh) compared to 37.6 TWh and 25 per cent in 2004.

Nuclear facilities continued to provide the majority of supply for Ontario, increasing their share of the province's electricity generation slightly to 51 per cent, or 79 TWh. Generation from coal-fired facilities was also up slightly accounting for 19 per cent, of all Ontario generation or 30 TWh. Other fuels, including oil, gas and alternative sources, supplied the remaining eight per cent, or 13 TWh, of the province's electricity output.

Ontario imported 11 TWh in 2005, up from the previous year when imports totalled 9.7 TWh. Ontario Demand plus the Operating Reserve that the IESO is required to carry exceeded the available domestic capacity in 593 hours during 2005, a 30 per cent increase over 2004.

Ontario's demand for electricity continued to increase. Ontarians consumed a total of 157 TWh in 2005, an increase of just over two per cent from 2004. This is partly due to increased load from air conditioners during the hot summer.