System strained, but holding up

Air conditioner-dependent Ontarians trying to beat the blistering heat used more electricity during peak hours July 17 than they have all year. But energy authorities say the power consumption was "manageable" and that the electricity system is holding up well.

"We've got very good performance from Ontario's generators," said Terry Young, spokesperson for the Independent Electricity System Operator, which manages supply and demand on the power grid. "We've said for some time now we're in better shape than last summer, and we're seeing evidence of that."

Peak power demand climbed to 25,898 megawatts, its highest level so far this year and third-highest on record. The all-time record of 26,160 megawatts was set last July.

By this time last year the province had already experienced more heat waves and three times as many extreme heat alerts, putting the electricity system under more pressure by drying up hydro-electric water capacity. The Pickering A Unit 1 nuclear reactor was also offline, leaving the province short of another 515 megawatts of power.

The crunch last year forced the province to reduce voltage levels across the grid three times by 5 per cent — once in April and twice back-to-back in early August. Voltage reductions, not required yet this year, are an emergency tactic that can free up about 500 megawatts of power.

The system operator also hasn't had to trigger its new Emergency Demand Reduction Program, through which some large commercial and industrial energy users agree to reduce their electricity consumption in exchange for payment.

"This is really just the first heat wave we've seen," said Young. "We're not seeing anywhere near the situation we saw last summer."

Energy authorities worried that peak power demand would come in at 26,192 megawatts, breaking the previous record. But that didn't happen, thanks to unexpected cloud cover.

This summer hydro-electricity capacity is holding up, and new power generation has been added.

For example, the Pickering A Unit 1 came back online last December after eight years out of commission.

A new 117 megawatt natural gas co-generation facility at Pearson International Airport is also contributing, along with new wind farms.

Ontario's three operational wind farms, which have a total power capacity of 207 megawatts, were contributing anywhere from 44 megawatts to 102 megawatts July 17.

Despite the added generation, the system operator was forced to issue a level 1 energy emergency alert — level 3 is the highest — indicating that the province is relying on imports from the United States and neighbouring provinces to meet some of its demand.

One complicating issue is that Ontario Power Generation's Darlington 3 Unit has been powered down for short-term maintenance and remained unavailable yesterday. The 880-megawatt nuclear unit is expected back in service early this week, according to OPG. This should ease import requirements.

"The big variable for us is the amount of generation available," said Young. "With the exception of the Darlington unit, everything seems to be performing well. If that holds true, there's no reason to think we won't be able to manage our way through this."

Chris Winter, executive director of the Conservation Council of Ontario, said that just because we can meet our power demand doesn't mean Ontarians should ignore conservation.

"Even though we're going to bust the record, the province is not issuing any appeal for conservation," said Winter. "We shouldn't have to be in a crisis situation to conserve."

The biggest culprit he said is air conditioning, which uses up about 40 per cent of peak electricity demand on the hottest days.

Winter said he's concerned about retail stores that crank their air conditioning systems high and keep their front doors open. He has been going door-to-door asking retailers to change their behaviour.

"Our message to the public is to support those stores," said Winter. "It's a procott, not boycott."

Young agreed that during any heat wave conservation must been encouraged and embraced.

"The system is strained," he said. "Everything you can do to cut back helps."