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Corporate IESO > Media > About Public Appeals > IESO Appeals for Reduced Electricity Consumption as Hot Weather Continues to Strain System

IESO Appeals for Reduced Electricity Consumption as Hot Weather Continues to Strain System

August 2, 2005

The Independent Electricity System Operator (IESO) is asking consumers to reduce their use of electricity for the remainder of the week as sustained hot weather continues to put a strain on Ontario's electricity system.

"The high temperatures and high humidity levels combined with limitations on Ontario's generating capacity are presenting a number of challenges for the IESO in managing the reliability of the electricity system," said Paul Murphy, Chief Operating Officer for the IESO. "Conservation efforts result in a reduced load on the system and provide additional operating flexibility when the power system is strained," added Murphy.

As a result, consumers and businesses are being asked to reduce the electricity consumption, where possible, between the hours of 8:00 a.m. and 8:00 p.m.

The voluntary appeal for reduced consumption is in effect until 6:00 p.m. Friday, August 5th. However, more immediate stronger appeals such as a Power Warning or Power Emergency may be issued if the situation deteriorates.

The IESO issues a Power Advisory when supplies of power, including imports, are forecast to be adequate, but the expected high demand will put a prolonged strain on the electricity system. Conservation measures will benefit consumers, the environment and the electricity infrastructure. Power Advisories can last for an extended period of time.

Consumers and businesses can reduce the demands on the electricity system by:

- Turning off all but essential internal and external lights;
- Setting air conditioners to 26 degrees Celsius or higher, or using fans as an alternative;
- Closing curtains and blinds to keep out the sun and retaining cooler air inside; and 
- Avoiding or limiting the use of major power-consuming equipment such as dishwashers, washers and dryers and swimming pool pumps between the hours of 8:00 a.m. and 800 p.m.

The IESO is responsible for managing Ontario's bulk electricity system and operating the wholesale electricity market. For more information, visit