“By 2030, overall global energy consumption may be 35 or 40 percent greater than it is today. The mix will probably not be too different from what it is today. Hydrocarbons will likely be somewhere between 75 and 80 percent of the overall supply. One can imagine a host of factors— from political upheavals and military conflicts to major shifts in the global economy to changes in pricing and regulation or significant technological breakthroughs— that change this picture more decisively. But that law of long lead times still remains. It is really after 2030 that the energy system could start to look quite different as the cumulative effect of innovation and technological advance makes its full impact felt.”
Yergin, Daniel (2011-09-20). The Quest: Energy, Security, and the Remaking of the Modern World (Kindle Locations 11661-11666). Penguin Publishing Group. Kindle Edition.