A 54 kW battery system does not sound like much power. It costs ~$100,000. But it is worth it to large hotels and others, because the power companies charge a premium for high-demand electricity. See:
http://www.theatlantic.com/technology/archive/2013/11/the-100-000-battery-that-could-help-hotels-save-bundles-of-money/281194/ Related story about rooftop solar systems at Walmart, Cosco and other corporations: http://qz.com/135517/the-us-corporate-boom-in-solar-power-explained-in-five-charts/ - Jed
