Awareness of the problem with biofuels is spreading, but Sean Carroll speaks more to this geek than Paul Krugman or the editors of Time:
Funny thing about energy: it’s conserved! …. We bring you this reminder because a knowledge of basic physics can occasionally be helpful when formulating public policy.
In particular, biofuels (such as ethanol) and hydrogen are not actually sources of energy — given the vagaries of thermodynamics, it costs more energy to create them than we can get by actually using them, as there will inevitably be some waste heat and entropy produced.
From Hilbert Space to Dilbert Space, and beyond 