Biofuels. Oh, how the mighty have fallen. What was once a darling of the green energy contingent has now been shown to be another bust by the 'if we mandate it, capitalism will love it and make it better' hope-over-reality segment of activism.

 The problems there seem much more grounded in fundamental biological constraints rather than technological ones. 
Well, they always were.  Jogalekar mentions the "much hyped ethanol-from-corn lobby" but we need to remember that the ethanol lobby really only got power after the mandates and subsidies rolled in.  It is rare (and difficult) to end funding once the government is involved.  Before the corn farmers were insisting these subsidies and mandates were necessary, it was environmentalists insisting this was solid science despite what (non-activist) scientists knew about the nature of photosynthesis.  From the late 1980s on, Senator and then Vice-President Al Gore gushed about corn ethanol and environmental activists were right in there with him.  

People are falling prey to similar hype about the Department of Energy porkbarreling current solar energy technology, 

http://wavefunction.fieldofscience.com/2012/02/end-of-biofuels.html
http://onlinelibrary.wiley.com/doi/10.1002/anie.201200218/pdf