Here is my argument:
The internal combustion engine is inherently inefficient, loosing more energy through heat and friction than it delivers to drive a vehicle forward. (see Electric v. Combustion engines) We don’t know what inventions will be transporting us around in 50 years time, but the likelihood that they bear much resemblance to a heavy lump of metal, generating heat and exhaust gases seems very unlikely. Therefore, any fuel which is produced with the intention of running a combustion engine are likely to have a limited life.
However, biofuels could be used to generate electricity. The question is are there circumstances where it is more efficient to grow, harvest, process and ‘burn’ a plant than to use wind, waves or sun to directly generate electricity?
Even though the future might be predominantly electric, there will always be niches. Butane Fuel Cells for small devices might replace batteries, and they can provide 20 times the run time of the current battery technology for the same mass. The choice would be recharge your device yourself anywhere you can plug it in or go and buy a butane charge for your fuel cell. Hmmm, think I’ll plug it in thanks and wait for the battery technology to catch up.
Wind, waves and sun are intermittent so some form of storage is required. Maybe biofuels will be best used for powering backup generation?
I’m not convinced of my own argument here, so hoping for someone to point out the flaws in it.