Arizona residents are going green faster than ever before, spurred on by utility credits and government tax breaks. Arizona Public Service reports that utility customers have installed more solar systems in the past year than in all prior years combined. "It is less expensive to purchase power from (large, utility-scale) wind farms, geothermal and biomass plants. But we recognize our customers want (rooftop solar systems), so we are providing them. ... We have decided that we want to meet customer demand," said Lori Singleton, manager of renewable energy programs at Salt River Project.