Monday, February 27, 2012

Nobel Laureate (Chemistry) "The Nonsense of Biofuels"

I feel a bit creepy doing the 'Argument from Authority'* thing but hey, Joe Romm's been trotting out "Nobelist" Gore or "Nobelist" Krugman whenever it suits his argument since at least 2007.
In some circles the prizes in the hard sciences are considered less political than the Peace Prize.
And the Economics prize isn't even a real Nobel.
From The Curious Wavefunction at Field of Science:
The end of biofuels?
Hartmut Michel from the Max Planck Institute of Biophysics has an editorial (open access!) in Angewandte Chemie with a title that makes his views clear: "The Nonsense of Biofuels". He essentially comes down hard on biofuel proponents of all stripes and not just the much hyped ethanol-from-corn lobby. Michel won the Nobel Prize for cracking open the structure of one of earth's most important proteins - the photosynthetic reaction center - so he certainly knows his photosynthesis.

He starts by looking at the energy efficiency of the process. It's not always appreciated that for all its rightly deserved glory, photosynthesis is not as efficient as we think, which would indeed be the case for something that's been tuned by evolutionary fits and starts and historical contingency. For one thing, UV, IR and green light cannot be utilized by plants so that leaves out a pretty high-energy part of the spectrum. Then there's all the wonderful machinery of electron transfer and light-harvesting proteins involved in the dark and light processes. The light step essentially captures photon energy and generates NADPH and ATP, and the dark step uses this energy source and reducing potential to synthesize carbohydrates from CO2. Considering the inefficiencies inherent in using the energy of massless, transient photons, only about 12% of energy from sunlight is stored as NADPH.

Then there's the question of light intensity which seems to invoke a classic catch-22 situation. At low intensities where the process is most efficient you don't have a lot of photons by definition. But try to improve the efficiency by bumping up the intensity and you get photodamage which, in Michel's words, 3.5 billion years of evolution hasn't been able to circumvent. To avoid this photodamage, plants have to recycle one of the key proteins in photosystem II about thrice every hour which inherently limits the efficiency. Finally, the key protein in the second step, RuBisCO, has a hard time distinguishing between CO2 and O2. A significant amount of energy has to be spent in getting rid of the product formed from O2 insertion.

All these hurdles lead to a rather drastic lowering of photosynthetic efficiency which gets watered down to a rather measly (but still staggeringly efficient by human standards) 4% or so.

It's pretty clear from this description that any kind of efforts to get better efficiency from biofuels will have to overcome enormous protein engineering hurdles. This does not bode well for current studies aimed at such goals....MORE
* See: "The Fallacy Files: Taxonomy of Logical Fallacies".

Also of interest, Schopenhauer's little gem "Die Kunst, Recht zu behalten" for tips on how to win debates:
Use Seemingly Absurd Propositions
Generalize the Matter, Then Argue Against it
State a False Syllogism
Appeal to Authority Rather Than Reason
Bewilder Your opponent by Mere Bombast
Put His Thesis Into Some Odious Category
Become Personal, Insulting, Rude (the Ultimate Stratagem)...

And many more. As I said, a little gem.