There’s a good article on biofuels this week in National Geographic Magazine. It explains in simple terms why ethanol and biodiesel, in the forms we now know them in the U.S., aren’t the answer to our concerns about global warming. I think this is particularly important to understand because biofuel is the renewable energy that politicians have rallied behind most enthusiastically, passing a Renewable Fuel Standard that will require 7.5 billion gallons of the nation’s fuel supply to be ethanol or biodiesel by the year 2012.
There has long been controversy over the “energy balance” of biofuels: the question of whether they take more energy to process then they produce when burned. Even if they are not net energy losers, its unlikely that they’re big winners either. That’s because both corn and soybeans produced by industrial farms require tons of nitrogen fertilizer to grow. Furthermore, many biofuel plants run on coal or natural gas, and corn must be refined into sugar before it is fermented into fuel, a process which releases a great deal of carbon dioxide.
Emissions aside, the real political obstacle for soy or corn-based biofuels is that they compete with the food supply. For the U.S., the most elegant way around this would be to make cellulosic ethanol from plant waste, but right now, existing cellulosic ethanol refineries are only 45 percent efficient, compared to about 85 percent for the average oil refinery.
The numbers on soy and corn fuels are particularly sobering for me, as I’m currently designing a project to run one of NYU’s vehicles on biofuel of some sort. Reading the National Geographic article helped boost my confidence in using Waste Vegetable Oil (WVO) as fuel. Like energy efficiency or freeganism, using WVO is a way of sustaining ourselves off of the excesses of our current system. It requires no new fuel production, but is merely providing a second life to a substance that was already headed to the rendering shop or the landfill. Until cellulosic ethanol comes along, you’ll find me pillaging WVO out by the loading dock, the smell of french fries wafting on the breeze.