Green roofs could save residents $211 annually
"If green roofs or cool roofs were installed on 50 percent of existing roof surfaces in southern California, it could save up to 1.6 million megawatt hours of electricity annually, enough to power more than 127,000 homes in California and save residents up to $211 million in energy costs each year… energy savings would cut carbon pollution by 465,000 metric tons annually.”
http://odewire.com/greenroofs