Originally Posted by
Checkboard
If you're going to "make" fuel from CO2 - where is the energy you're going to need to do that coming from? The local coal powerplant? That's on top of the energy cost of collecting the CO2 in the first place, when it only makes up 0.04% of the atmosphere. (So, if you have a 100% efficient collection process, getting a ton of CO2 will need you to pass 2500 tons of air through your collector - and those pumps and whatnot are lost cost - you haven't even started trying to reduce the CO2 to hydrocarbon fuel yet.)
The idea of 'making' hydrocarbon fuels is not new (think of the synthetic petroleum the Germans used during WW II) - although the rational is changed. The Germans used coal to make petroleum - the new plan is to make petroleum from CO2 and hydrogen using
excess electricity. It won't be cheap, and it's dependent on a plentiful supply of '
green' electricity, but it's far from pie in the sky. One of the problems with most 'green' electrical production is that it isn't consistent (solar) or reliably predictable (wind), meaning sometimes you're going to have large surpluses or large shortages. Using those periods of large surplus to manufacture hydrocarbon type fuels is one way to balance out the peaks and valleys.
Personally I think bio (algae) based hydrocarbon fuels are the future of aviation, but assuming we can create large scale 'green' electrical electrical generation, manufacturing hydrocarbon fuels is certainly a viable option.