Maybe in 100, 500, 1,000, or 5,000 years when the fossil fuels are finally gone. Fundamental economics will take care of the problem when the time requires it.
There may be no “fossil” fuels. Companies are finding oil almost everywhere once they get down several miles. The theory is oil is created by deep planet bacteria. Wells that were “dry” in the 1940’s are pumping again. If the fossil theory was true they’d go dry and stay that way. (See book at url.)
http://www.amazon.com/The-Deep-Hot-Biosphere-Fossil/dp/0387952535