Originally posted by @wildgrass
...What is the energy cost to produce?
This is an important question because if it takes more energy to produce it than the amount of useful energy (i.e. minus the energy loses from energy conversion) that can realistically be extracted from it after it is produced, there's no point in it. I don't know the relevant figures on that. But obviously there must be some net gain in usable energy from it for it to be of any use.
Many years ago, I once heard of a research project to produce biofuel from sugar beet crops.
At first many peopled thought the research project seemed to be going very well with lots of biofuel being produced until it disastrously all completely fell apart when someone noticed that the amount of fuel the farm machinery needed to grow the sugar beet was more than the amount of biofuel that was being produced from the sugar beet; -they really hadn't thought that one through at all.
...and those that don't learn from history are doomed to repeat it.