Residents and businesses in Brock Township are being urged to shut off their lights in unison March 29 to support a global initiative.

Council recently voted to accept a challenge from Ajax to take part in a voluntary Earth Hour blackout, which would see those taking part turn off their lights from 8 to 9 p.m. on Saturday, March 29.

A growing number of municipalities across Ontario, including Toronto, are signing on to the worldwide initiative. The event originated in Sydney, Australia last year and reduced the city's energy consumption by 10.2 per cent.

"If all business and residents in Brock Township accept the challenge as well, we can make a huge difference in the amount of energy consumed," said regional councillor John Grant.

Durham schools are also taking part.

"Between 10 and 11 a.m. we'll turn out the lights. We'd like to report back on the number of schools participating so we can see how much energy we're saving," Judy Gould, energy/waste officer for the Durham District School Board.

Schools in the DDSB already turn out their lights in the evenings and on weekends, said Ms. Gould, so the best way of making the hour unique would be to hold it on a school day.

The local hydro company is also on board.

George Armstrong, spokesperson for Veridian, which supplies power to Brock Township, said, "We encourage our customers to conserve not only during Earth Hour but year-round."

He said results about the impact of the hour of darkness will be made public following the event. When asked what the risk of potentially having a large volume of households flick their light switches back on collectively at 9 p.m. that day, he said Veridian customers will not be affected.

"We'll be able to withstand (it) when the lights are turned back on," he said.

The idea is to turn off only lights, not other equipment, "to create a nice dark sky."

However, Lisa Pearson, spokesperson for the Independent Electricity System Operator (IESO), which directs the flow of electricity around the province, said the IESO is "trying to determine possible impacts" of the Earth Hour blackout on hydro supply.

She said it's a bit too soon to say, as the final numbers of how many participants there will be on March 29 has not been determined. But she added, "I wouldn't categorize it as a risk... demand (for power) changes every hour of every day."

She also noted the IESO will monitor power levels on March 29, and "have a contingency plan in place" if needed.

According to the Earth Hour website, as of Thursday at 1 p.m., 54,238 people and 3,182 businesses around the world had registered to take part.

For more information, or to register, visit  www.earthhour.org