Edmontonians who stepped outside last night to see how the city was dealing with Earth Hour could be forgiven if they saw little difference.

The annual event, observed in cities around the world, is meant to see consumers reduce their demand for electricity.

And Edmontonians did manage to do that, consuming 921 megawatt hours of electricity during Earth Hour on Saturday night,  said EPCOR spokeswoman Nikki van Dusen. The figure is down from last year, when the city drew 1,082 megawatt hours.

However, that’s where the simple comparison ends.

EPCOR also measured power consumption from 7:30 p.m. to the start of Earth Hour at 8:30 p.m. The result? Edmontonians actually used more power during Earth Hour than in the hour that preceded it.

This shouldn't be seen as surprising, said van Dusen on Sunday: "The most significant influences on power consumption changes are weather and hours of daylight."

The sun set in Edmonton at 7:54 p.m. on Saturday, which might explain the slight hike in power.

There was also an Edmonton Oilers hockey game on Saturday night, van Dusen added.

Comparing the Earth Hour figures against the totals recorded a week earlier during the same time period showed a three per cent decrease in energy consumption. However, it is unclear how much of that reduction was due to energy conservation efforts, according to van Dusen.

"It’s hard to say," she said. "It is normal to see a variation of plus or minus 10 per cent when comparing any given hour’s power consumption to the previous week’s figure."

The final complicating factor in determining how many Edmontonians turned out the lights is the nature of the event itself, said van Dusen.

"Earth Hour only asks us to turn off lights," she said. "In today’s wired society, there are a lot of things plugged in that are drawing power regardless of whether we’re using them."