There was a book written years ago that I read that thought that gas would keep increasing in price until it was $20/gallon US (3.79 liters). It was written before the big boom in fracking I think. Anyway the whole book was, what would happen, how fast would people change to alternatives or fund alternative research, etc. I thought it was an interesting take, because it rested on the idea that corporations won't change unless they are forced to, and people will freak out and demand change when the price is too high.