La cita

Mr. Greenstone and Mr. Looney estimate that a coal plant must spend 3.2 cents to produce a kilowatt hour of electricity (and consumers then pay slightly more than this). This price appears to be a bargain, the economists write, but the true costs — once health costs, military costs and the like are taken into account — are more than twice high: 8.8 cents per kilowatt hour.

Vía http://economix.blogs.nytimes.com/2011/05/18/the-true-cost-of-carbon/