[thackney]

require that San Francisco get 51 percent of its electricity from renewable energy sources

No problem. When the demand in the city reaches twice those resources, PG&E can just turn off the power to San Fran.

[dblshot]

Supply of green energy can be achieved only with higher prices and or subsidies. When their electric bills soar you think San Franciscans will be proud of their green system and willing to pay for it or go for subsidies from the rest of us evil pollution producing energy users? Eventually God is going to remind of us that Proverbs 2:1-10 can be done again.