“But under any external-cost scenario, coal’s price advantage erodes. Natural gas becomes a more cost-efficient generating fuel, since it emits less sulfur. More important, renewable resources like geothermal energy, wind, and solar energy, at five to twelve cents per kilowatt hour, suddenly become competitive, because they carry few or none of the external costs associated with coal.”

— “The True Cost of Coal,” Atlantic Monthly, Dec. 1993