Since gasoline hit $3 a gallon, suddenly words like "biodiesel" are being heard a lot more often. Maybe this oil crunch could provide impetus to finally get us moving toward renewable energy.
The problems with these technologies are the usual ones with fossil fuels: environmental damage to extract the fuels, and carbon dioxide emissions when burned. Both involve mining, seldom environmentally benign. Shale oil is locked inside of rock and must be melted out, a process that apparently consumes a lot of water.
And they're still limited resources. It would be sad indeed if we put all our research and development into squeezing the last few drops of oil out of the rocks to get another 20 years of fossil-fuel economy which then collapses, rather than devoting those resources to sustainability now.