INDEPTH: ENERGY
Blackouts and brownouts
CBC News Online | June 29, 2005
Whenever the temperature spikes or plummets for extended periods, the words electricity blackout and brownout become part of our water cooler conversations. But what do those two terms mean, and what are their implications?
As it turns out, brownout is a dated term that has lost its currency. "It's an old term that describes reduced voltage," said Terry Young, spokesman with Ontario's Independent Electricity System Operator [IESO], which manages the province's power supply. "Twenty-five to 30 years ago, we had brownouts. When you did reduce voltage, you'd see a dimming of lights and your TV screen would shrink."
Today's manufacturers of home appliances and industrial equipment have adapted their products to the periodic voltage fluctuations that were once associated with brownouts.
In fact, every 18 months or so, utilities across Canada reduce the voltage running through power lines by three to five per cent for an hour at a time, just to test the system. That's because they want to be sure there will be no problems when they actually need to reduce voltage during times of peak power demand – in the midst of heat waves and cold snaps, for example.
The term blackout, on the other hand, continues to have meaning today – just ask anyone living in Eastern North America during the Aug. 14, 2003, blackout that plunged 50 million people into darkness.
A blackout is a complete interruption of power in a particular area. There are two types: ones that are unplanned and ones that are planned.
Unplanned blackouts can occur when there is an equipment failure, such as when transmission lines can't handle increased energy loads. The August 2003 blackout happened after a series of failures that began with an Ohio electricity provider and triggered a cascade effect that caused the lights to go out on both sides of the border.
Planned, rotating blackouts occur when demand for energy peaks and all avenues for reducing demand have already been explored. In essence, it is an enforced shedding of energy demand. Usually, local utilities are responsible for deciding what areas can best handle blackouts.
"Toronto Hydro might say the TTC [Toronto Transit Commission] is a priority load or the hospitals are a priority load, and they'll decide where to cut," said the IESO's Young.
But electricity operators do everything they can to avoid blackouts. Before energy demand approaches a system's ability to cope, both residential and industrial customers are asked to cut back voluntarily.
In Ontario, where demand is high because of its large population and industrial base, the province can generate as much as 25,600 megawatts on any given day. When demand exceeds that, it's time to start turning off electrical equipment.
"We have agreements with some companies that will not use energy when we ask them," said Young.
During Ontario's June 2005 heat wave, the provincial government also asked the federal government to reduce power usage. Workers in federally owned buildings in Ontario were asked to use air conditioners sparingly, switch off lights during the day, and computers and photocopiers at night.
When demand continues to outstrip supply, despite conservation measures, then it's time to buy energy from neighbouring provinces or states. And that's energy that comes at a steep price.
In Ontario on June 24, 2005, prices on the electricity spot market shot up to 28 cents per kilowatt-hour. That compares with an average price of seven cents per kilowatt-hour for the month of June.
Residential customers are shielded from such spikes. They pay five cents for the first 750 kilowatt-hours and 5.8 cents for everything above that.
But some businesses buy their power on the wholesale spot market and feel the full effect. "I was talking to a big manufacturer in Ontario, an automotive company, and they estimate over the last week [the spike] has cost over $200,000," said Jayson Myers, senior vice-president with the Canadian Manufacturers and Exporters.
Other companies have long-term contracts for energy that may be affected by price spikes when it comes time to renegotiate. "It certainly has an impact on the bottom line," said Myers.
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