BEIJING, Dec. 5 (Xinhuanet) -- Following in the footsteps of billboards in Canada and Africa, a California electricity provider says it installed America's first solar-powered billboard that makes more electricity than it uses.

    The billboard -- topped off with 20 solar panels -- is located at 1000 Brannan St. in San Francisco, and is visible from the Highway 101 9th Street exit.

    "The energy that is collected by the solar panels actually exceeds the amount used by it on a day-to-day basis," said Pacific Gas and Electric (PG&E) spokesperson Jennifer Zelwer of the standard-sized billboard, which proclaims: "This isn't a billboard. It's a power plant."

    On sunny days, the sign converts sunlight into about 3.4 kilowatts of energy, which is almost enough to power the household of an average U.S. family of four during the day. Zelwer said the billboard generates about 2.5 kilowatts of energy during cloudy days.

    Although the billboard does borrow electricity at night, she said it has other green-technology tricks up its sleeves to keep the ratio of energy produced to energy consumed in the positive, including diode lights that use less than a third of the energy needed by standard halophane lights.

    PG&E's new solar-powered billboard isn't the first in the world, as both Canada and Africa already have them. But Zelwer said it is the first in the Americas to actually push power onto an electrical grid, like ones in Africa do.

    (Agencies)