Quote:
Originally Posted by Rasputin_Vol  How many Joules does it take to create 1 J of energy from this algae process?  |
For traditional biodiesel (soy), the number is about 3.2 Joules of biodiesel per Joule of traditional energy input (not counting the sun's input, that is). So, the Energy Return on Energy Investment (EROEI) is 3.2. Because the yields of algae are supposed to be A LOT higher per acre, then the EROEI for biodiesel from algae would likely be higher.
However, this is highly dependent on the scale of use...because if we really step up production, then we would likely need a lot more space...which means the dessert, probably. While the solar energy is a lot more prevalent there...water is not...so I would think that the EROEI would fall down some. I can't find a good analysis of this, though. Something else to remember is that processes like this do not see very good economies of scale...so increasing the scale would not necessarily save money in aspects like capital investment.