Electricity facts

The Globe and Mail - August 19, 2003

The essence of the megawatt crisis facing Ontario is that unless switches are turned off, someone may have to go without electricity.

Staying in power

Electrical generators that were in working order in the province yesterday produced a total of 19,700 megawatts. Think of it as enough juice to keep 197-million 100-watt light bulbs on at the same time.

1MW = (one lightbulb) X 10,000 (100-watt)

On a hot summer day, Ontarians typically burn through 22,000 megawatts of electricity. But yesterday homes and businesses heeded the province's warning to power down, said Chris Eby, spokesman for Energy Minister John Baird. Morning peak use was 17,250 megawatts. Afternoon peak use rose to 18,100 megawatts, leaving a thin margin for error, according to the Independent Electricity Market Operator, which manages the province's wholesale power sales.

19,700 MW available
22,000 MW typical use
17,250 MW a.m.
18,100 MW p.m.

Down time

Technically, Ontario's nuclear, fossil fuel and hydro generators could product up to 30,500 megawatts of power a day. They don't run all the time, however. Nuclear and hydro plants are designed to provide continuous power, but are in service between 70 and 80 per cent of the time because they need maintenance. Coal-burning plants provide extra power during high demand times, and are designed to operate only about 40 to 60 per cent of the time. Natural gas and oil plants are the most expensive to run. They run only 10 to 30 per cent of the time, when electrical demand is the highest.

Typical Operating Duty:
Nuclear and hydro: 70-80%
Coal-burning: 40-60%
Oil and gas: 10-30%

Imports and exports

A complex system of generators and transmission lines known as the Lake Erie loop moves power through Ontario that may be generated in Ontario, Michigan, New York or Quebec. Yesterday, Ontario was getting reserve power from Quebec and Manitoba and some that was generated as far away as the southern United States, Mr. Eby said.

Nuclear dependence

Ontario is heavily dependent on its nuclear plants, which represent as much as 45 per cent of the province's electrical production

Nuclear: 45%
Other: 55%

Visit the Globe and Mail newspaper today