In an effort to conserve energy and raise awareness, a local group is urging all Santa Barbarans to turn off their lights for an hour at 8 p.m. on Saturday.

The newly formed Lights Out Santa Barbara is part of a wider coastal effort that includes the cities of San Francisco and Los Angeles.

Saturday night will mark the first time the event has occurred in the United States. The idea originated in Australia, where, on March 31, more than 2 million residents of Sydney clicked off the lights in recognition of what they called “Earth Day.”

As a result, energy use across the city fell by 10 percent. This reduced carbon dioxide emissions by 24.86 tons, which amounts to taking some 48,000 cars off the road for an hour, according to the local group’s Web site .

Locally, organizers are hoping to reduce emissions by a similar percentage.

“What appealed to me the most was how simple it was, how easy it was, how voluntary,” said Phyllis de Picciotto, who spearheaded the grass-roots drive to start a local contingent of Lights Out. “A lot of times, you look at things that are big — like climate change — and ask, ‘What can I do?’ This is measurable.”

De Picciotto learned about the idea around a month ago, by reading an article about the Lights Out project in San Francisco. Initially, she thought she’d shoot for an event in January or February. But after talking with the founder of the San Francisco group, she was inspired to kick it into high gear.

Word is spreading. She and other advocates have fanned out to organizations such as the Santa Barbara City Council, Chamber of Commerce and Southern California Edison, and a growing number of people have added their names to Lights Out Santa Barbara’s online list of supporters.

“We would love thousands of people to be volunteers for this event, and to tell their friends,” she said. “It is totally word of mouth.”