Backgrounder articles on the comparative viability of various alternative energy sources:
http://peakoiltas.org/2011/05/the-alternatives-to-oil/
http://peakoiltas.org/2011/08/problems-with-alternative-energy/
The bottom line for any energy producing enterprise is EROEI.
Get that wrong and it’s a dead duck.
Every day developers are coming up with dozens of ways that energy can technically be produced, but almost no bio-fuel projects end up with a satisfactory enough EREOI (energy returned on energy invested) to become commercially viable – i.e. without subsidy.
In the worst cases (as with ethanol produced from corn in the US) more energy is consumed in its production that what it produces, so the whole process is a sort of subsidy to satisfy corn growers and should not be considered as an energy producer.
In the case of tar sands from Canada, the EROEI is so low that much of the energy produced from the process is used to fuel the production process and, thus the greenhouse emissions from that enterprise is quite shocking. (The aim of the exercise there is a political one, to try to get away from imported Middle East oil supplies.)
I don’t have inside knowledge on the mooted ethanol-from-eucalypt project but expect that its EROEI must be somewhere down in the bottom end order of 3 to 1 ratio. I expect even lower.
Note that the EROEI that is needed to maintain the sort of society that we have is estimated at around 12 to 1 ratio. This is the bottom line reality check for such mooted alternative energy schemes.
Desperation to supply liquid fuels as world oil supplies become more costly ad difficult to access is what is driving these multiple endeavours. Most of them will founder or not start up at all because the potential investors have to accept the risks involved.
