Imagine if more cities started doing this — neutralizing the upfront costs of solar. It would stimulate competition and innovation in the solar industry (more than there already are). Pretty soon there would be large economies of scale for solar power and the price would drop (faster than it already is). More cities would be lured into the program, stimulating yet more innovation and lower prices. So on and so on, the cycle of smart long-term investment. Tell me again why we think tackling global warming has to be expensive?