Potholes on the road to a green future
September 8, 2009 2:49 PM Subscribe
posted by Diablevert (19 comments total)
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Inspired by a recent Wall Street Journal* article, Robert Rapier
, chemical engineer, peakist, blogger, and currently chief technology officer for a bioenergy company, reviews the pretenders
, and niche players
in the emerging field of green energy, with particular consideration of liquid fuels. Meanwhile, the boffins at Foreign Policy consider the risks of the coming of the green energy era
, and depict the end of the oil age.
(Both part of FP's extensive look at the end of oil
Being an engineer, Rapier discusses some hard numbers that give a sense of the dimensions of the challenge the industry faces. From his contenders article: “Consider for a moment the amount of energy locked up inside the 1.3 billion tons of dry biomass that the Department of Energy suggests can be sustainably produced each year. Woody biomass and crop residues - the kind of biomass covered in the 1.3 billion ton study - contains an energy content of approximately 7,000 BTUs per pound (bone dry basis). The energy content of a barrel of oil is approximately 5.8 million BTUs. Thus the raw energy contained in 1.3 billion tons of dry biomass is equivalent to the energy content of 3.1 billion barrels of oil, which is equal to 42% of the 7.32 billion barrels the United States consumed in 2008.
This calculation tells you a couple of things. First, the 42% represents an upper limit on the amount of oil that could be displaced by 1.3 billion tons of biomass. The true number would be much lower because energy is required to get the biomass to the biorefinery and then to process it. So replacing oil with biomass isn't going to be a trivial task, and a process must be capable of turning a respectable percentage of those biomass BTUs into liquid fuel if it is to be a contender.
*Paywall, if encountered, may be averted by searching article title on google and entering from there.