The Independent Electricity System Operator (IESO) reported that compared to a typical Saturday night in late March, demand for electricity in Ontario was down 2.7 per cent or 423 megawatts (MW) as a result of Earth Hour. This drop is slightly higher than the peak energy needs of a city the size of Burlington.
In periods of tight electricity supplies, the IESO may issue a public appeal urging consumers to reduce electricity consumption.
Typically, public appeals are issued when extreme weather or unexpected generator outages stretch the system's ability to provide enough electricity to meet demand and required levels of reserve.
• Full list of public appeals since May 1, 2002.
