The environmental impacts of fossil-fueled electricity drive interest in a cleaner electricity supply. Electricity from wind provides an alternative to conventional generation that could, in principle, be used to achieve deep reductions Γ°450%Γ in carbon dioxide emissions and fossil fuel use. Estimates of the average cost of generation-now roughly 4b=kWh-do not address costs arising from the spatial distribution and intermittency of wind. The greenfield analysis presented in this paper provides an economic characterization of a wind system in which long-distance electricity transmission, storage, and gas turbines are used to supplement variable wind power output to meet a time-varying load. We find that, with somewhat optimistic assumptions about the cost of wind turbines, the use of wind to serve 50% of demand adds $ 1-2b=kWh to the cost of electricity, a cost comparable to that of other large-scale low carbon technologies. Even when wind serves an infinitesimal fraction of demand, its intermittency imposes costs beyond the average cost of delivered wind power. Due to residual CO 2 emissions, compressed air storage is surprisingly uncompetitive, and there is a tradeoff between the use of wind site diversity and storage as means of managing intermittency.