When people promote coal as clean and cheaper than renewable energy, keep this excellent quote in mind from Carl Safina:
"For one thing, the economy must include the true costs of things in the price of things. For instance, coal is very “cheap” because the price does not include the costs or ruining mountains, miners’ health problems, acid mine runoff into streams, global warming caused mainly by burning coal, acidification of the ocean which is killing shellfish and degrading coral reefs that millions of people rely on, and putting mercury in fish. All those things are real costs of coal, but they’re not in the price.
Coal is priced cheap, but it’s really the most costly fuel we use. Who pays those costs? We all do. If those costs were included in the price of coal, coal would be very expensive, and better, cleaner energy technologies would be very competitive."
It's from a great interview in Mongabay.com.