How many windmills could we build for the cost of one clean coal plant?

Coal is abundant and cheap, assuring that it will continue to be used. But the failure to start building, testing, tweaking and perfecting carbon capture and storage means that developing the technology may come too late to make coal compatible with limiting global warming.“It’s a total mess,” said Daniel M. Kammen, director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley.