By Evan Ackerman
Apparently, this billboard in San Francisco isn’t just hype: it is, in fact, a power plant, using 20 solar panels to generate more electricity during the day than it consumes lighting itself at night. On a sunny day, the billboard generates 3.4 kilowatts of energy, which is just about enough juice for a family of four during the day. If it’s cloudy, the output drops to 2.5 kilowatts. PG&E does not, of course, say how much the solar panels cost to buy, install, and maintain. My guess is that it’s in the “you’ll recoup the cost in a decade or so” range. Still, since we’ve got ugly billboards set up all over the place anyway, wouldn’t it be great if they could be put to some practical use besides annoying consumers out of purchasing whatever they happen to be advertising?