Wednesday, December 19, 2007

Biofuels: an extremely bad idea

The push for biofuels continues in spite of plenty of good, sound reasons why this is a massive mistake. Even greenies have fallen into this. I expect biofuels will ultimately prove to have been one of the biggest errors in energy policy of this century. The major problems with biofuels all boil down to some basic, inescapable ecological and thermodynamic realities. First, to summarize the problem:

Set aside issues of energy payback and whether you even get more energy out of the fuels than it took to make them, and assume this problem will be solved. Even so, to generate enough biofuel to begin to satisfy current levels of petroleum consumption would require converting most of the arable land on several continents to energy production. The effects of this on food supply as well as the massive clearing of land that this would (is already) lead to would probably make the biofuels industry even more environmentally destructive than, and at least as socially disruptive as, the fossil fuel industry is now.

But why? It seems like such a nifty idea on principle; why won't it work? Ecological thermodynamics, my dear Watson. Biofuel is fundamentally solar energy. But, this solar energy has been captured by an exceedingly inefficient collector (living plants) that only fixes a small percentage of solar energy as chemical energy. And of the stored chemical energy produced (i.e. biomass), only a modest fraction of this is useable for liquid fuels whether you are squeezing oil or fermenting ethanol. When your desired end product is basic, bulk energy on a massive scale, it is downright idiotic to manufacture this from such a complicated and inefficient (in terms of bulk energy transformations) mechanism as biology. Biology is unparalleled for creating biochemical complexity. If you want to create food or pharmaceuticals out of sunlight, plants and animals are the way to go. But if all you want to do is convert solar joules into mechanical or electrical joules, inserting a living system in the loop is like tying 10 tons of lead weights to the bumper of your car -- with no skids or wheels. Build a windmill. Construct solar-driven boilers and steam generators. Set up PV arrays. Develop better electrical storage systems. Sure, all these technologies have their dirty aspects and efficiency issues. But they constitute far more direct connections between raw, dispersed solar energy and the ultimate mechanical work or thermal energy derived from it.

Let's hope the biofuels fad is just that -- a fad, soon to be forgotten in the light of good judgement about what the biosphere can truly provide and endure.


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