Arizona has activated one of its largest grid battery storage projects to help meet peak summer energy demand. Electrek reports: Recurrent Energy, a subsidiary of Canadian Solar, just brought its 1,200 MWh Papago Storage facility in Maricopa County into commercial operation. The big grid battery is now supplying stored electricity to Arizona Public Service (APS), the state's largest utility, in time for peak air-conditioning season. Papago is the first of three Recurrent projects with APS. Together, they'll provide 1,800 MWh of storage and 150 MW of solar power. That's enough to run about 72,000 homes for four hours and provide year-round solar for another 24,000 homes.