The number of homeowners who say they plan on turning off the lights for Earth Hour this year has risen nearly 25 per cent, according to a recent survey.

About 73 per cent of those asked say they plan to power down for the annual global climate change event. Earth Hour will be observed in more than 250 Canadian cities this Saturday at 8:30 p.m. for one hour.

The survey's prediction of this year's participation level is notably higher than the 51 per cent who said they would take part last year.

The study was conducted by Ontario's Independent Electricity System Operator (IESO) between March 8 and 11. The telephone questionnaire was completed by 851 random Ontario homeowners.

"The increasing support we are seeing for Earth Hour is one indication that Ontario consumers are starting to show an interest in managing their electricity use in support of broad environmental goals," says Paul Murphy, president of the IESO.

"The findings in our survey also show residential consumers want to take a more active role in controlling their energy consumption – and their energy costs."

Ontarians' actions during Earth Hour 2009 led to an overall drop in electricity demand of 920 megawatts when compared to a typical Saturday night in late March.

Earth Hour is organized by the World Wildlife Fund as a show of support for action on climate change issues. It began in Sydney, Australia, in 2007.

WWF says more communities in Canada have signed up to participate than in any other country worldwide.

With files from The Canadian Press