All new buildings in San Francisco with 10 floors or less must install rooftop solar panels starting in 2017.  The Better Roofs Ordinance is expected to add 50,000 solar panels and avert 26.3 million tons of carbon dioxide annually—equivalent to emissions from 5,000 cars driven for a year. San Francisco’s ultimate goal is to power itself with 100% renewable energy. Larger buildings are exempt from the ordinance for now. The city has also pooled residents’ and business’ electricity demand to purchase bulk renewable energy from solar, wind, bioenergy, geothermal, and hydroelectric sources at competitive rates. The utilities commission estimates the average San Francisco homeowner is paying less than Pacific Gas and Electric’s standard rates for greener power, and only $6 more per month for those who request a 100 percent renewable mix.