After a pretty successful run last year, making a return engagement this Saturday night is Earth Hour, and Toronto Hydro is asking How Low Can We Go TO?

"Earth Hour is an important initiative to remind Torontonians about the importance of conserving electricity," says David O'Brien, President and CEO of Toronto Hydro Corporation. And that's why Hydro is sponsoring the How Low Can We Go TO contest, offering ten $250 prize packs of eco-minded gear (crank flashlight! solar backpack! solar clock!) for the brilliant (or lucky) among us who correctly guess how much Toronto's electrical demand will drop when we all shut off our lights.

But will we collectively turn out the lights as much as last year? Are there any other tricks up our collective sleeves for going low? Will any of this make a difference?

"The simple act of turning off the lights can make an incredible impact on the electricity grid and the environment," says CEO O'Brien. "We're encouraging everyone to participate and this contest is a fun way to get involved."

Last year during Earth Hour, Toronto dropped its electricity demand by 8.7 per cent - that's the equivalent of taking 262 megawatts off the grid, or approximately 5.8 million light bulbs.

This year Toronto Hydro is encouraging us to use battery-powered laptops (connected, I presume, to plugged in internet connections) to follow the drop in Toronto's electricity usage, live, as it happens Saturday night.

It all goes down this Saturday, March 28, 8:30 - 9:30 pm. I'll be watching with a front row seat from Toronto Hydro's "top secret" control room. Where will everybody else be?

Photo by Denmar.