San Francisco residents may soon have a chance to power their homes and businesses with "100 percent" certified green energy. But it won't come cheap. Under the CleanPowerSF program adopted Tuesday by the city's Public Utilities Commission on a 4-0 vote, San Francisco's 330,000 utility customers would be able to get all their power from wind, solar and other renewable sources, starting as early as July 1. On the downside, typical residential customers would also see their bills rise - at least in the short run - by anywhere from $7 to $54.50 a month, depending on their usage. That's...