Paul Krugman links us to this eye-popping paper by Muller, Mendelsohn, and Nordhaus, whose abstract reads in part:
Solid waste combustion, sewage treatment, stone quarrying, marinas, and oil and coal-fired power plants have air pollution damages larger than their value added. The largest industrial contributor to external costs is coal-fired electric generation, whose damages range from 0.8 to 5.6 times value added.
That’s right. It costs almost as much or more to burn coal than it adds to the economy. If we just shut down all coal plants, we’d be richer.