
Coal
"At one level, it's a surefire scheme. As coal eventually runs out, it will become very expensive. Even a combo wind/solar/geothermal/smartgrid solution will be cheaper one day. RE really will be < C."
In a few hundred years then, coal levels are still quite high, especially with the coal reserves found off the Norwegian coast in 2005 (enough to supply the worlds requirements for a few hundred years), they just need to find a way to get it out :)