Electricity consumption was down one per cent in Calgary during Earth Hour, a reversal from last year when Calgarians actually used more power.

Calgary residents were asked to turn off their lights between 8:30 p.m. and 9:30 p.m. on Saturday as part of a worldwide movement to raise awareness about energy consumption.

In 2008, electricity consumption in Calgary actually went up 3.6 per cent during Earth Hour. But this year, power provider Enmax recorded a one per cent reduction in electricity use, or about 10 megawatts.

"While that doesn't seem particularly significant … to me it's a positive move. It shows more Calgarians are on board this year with actually helping to reduce that energy consumption," said spokeswoman Doris Kaufmann.

Both years, the Flames were playing in the Saddledome, which "always contributes to the draw on the power," she said. But last year, Earth Hour was unseasonably cold in Calgary compared to this year.

Calgary residents weren't the only ones who switched off their lights this year. The power was off at the zoo and several commercial buildings, including the Calgary Tower, while the city turned off non-essential lights in all its buildings.

About 100 people gathered at the Outdoor Resource Centre on Memorial Drive with candles to watch the downtown skyline dim.

Astronomers at the Rothney Astrophysical Observatory southwest of Calgary had hoped to measure the change in the sky's brightness, but the weather didn't co-operate.

"The snow started to come down at eight and by 8:30 we were surrounded by snow," said astronomer Phil Langill. "The snow skunked us and we couldn't make any good observations at all."