John A. Baden: "Is Ethanol a Pure Green Elixir?"
Those of us committed to Green causes often respond more strongly to symbolic values than to careful analysis. Recycling offers a clear example. The environmental value of recycling depends on time- and place-specific circumstances. It almost always makes both ecological and economic sense to recycle aluminum and other metals. Often this holds for paper, only occasionally for plastic and glass. Recycling plastic and glass often consumes more resources than it saves... [in California the taxpayers will take up the slack]
Here’s CU’s [Consumer Union's] evaluation of ethanol. First, the energy content of ethanol is low when compared with gasoline or diesel. While diesel contains around 140,000 Btu per gallon, and gasoline 115,000 Btu, denatured ethanol contains only 78,000 Btu per gallon. We can’t cheat physics. These numbers translate into low fuel mileage.
CU tested a new Chevy Tahoe. “In highway driving (on 85 percent ethanol), gas mileage decreased from 21 to 15 mpg; in city driving, it dropped from 9 to 7.” In marked contrast, we have two old diesel ranch trucks that weigh a ton more than the new Tahoe and each gets 20+ mpg on the highway at 65 mph.
We can grow the feed-stocks for ethanol -- but I’d feel a bit guilty for using it. And not only for the subsidies built into its production.
Let’s consider one among many egregious ethanol subsidies. Flexible fuel vehicles (FFVs) are designed to run on either gasoline or a blend of 85 percent ethanol and 15 percent gas, E85. Automotive manufacturers receive generous fuel-economy credits for each FFV built -- even if it never runs on E85. This credit enables them to build more large SUVs that burn more gas than ethanol replaces. This is a perverse but predictable outcome of political forces.
The cellulosic ethanol touted by both Greens and President Bush may be a worse one for Third World ecosystems. What could be wrong with using carbohydrates to replace hydrocarbons? Here are some unintended consequences foretold by Peter Huber, an MIT engineering Ph.D.: “To improve on wood-burning fires, or grass-eating cows, perfect the cellulose-splitting enzyme. Then watch what 7 billion people will do to your forests and your grasslands.”
h/t: Dick McDonald