By 2030 the Energy Information Administration estimates that worldwide demand will be 105 million barrels a day, while current world output will only able to manage 43 million barrels a day, says a report by the Christian Science Monitor.
The EIA's Glen Sweetnam, who charted the shortfall, shows that fracking won't make a dent:
[Many] people will say that we already have a large new resource of tight oil (often mistakenly referred to as shale oil) which can be extracted through hydraulic fracturing or fracking. But even if the optimists are correct–and there can be no guarantee that they will be–this source of oil will only add 3 to 4 million barrels of daily production. What Sweetnam's chart tells us is that we must find and bring into production the equivalent of five new Saudi Arabias between now and 2030 in order to meet expected demand even if the volume of tight oil reaches its maximum projected output. (The Saudis currently produce about 11.7 mbpd of oil and other liquids.)