Wednesday, March 29, 2006

Environmental Science, Ethanol

This article, from the Manhattan Institute's Peter Huber, during the public discussion around ethanol, is a good look at the often undisclosed truths behind the latest push for creating or expanding a new technology promising to help our environment.

Using flesh-eating bacteria as an analogy to the products biochemists and genetic engineers would need to produce to enable this latest, is a wake-up.

Here is an excerpt.

The Forest Killers
Peter Huber 04.10.06

Now the green-energy crowd is touting cellulosic ethanol. This is a blunder, one they will regret more than any of their previous blunders. It will level forests, destroy wetlands and disrupt ecosystems all around the globe.

Or at least it will if the enabling technology ever becomes economical. And it might. Even a Republican President, in a State of the Union address, resolved to develop the technology "for producing ethanol, not just from corn, but from wood chips and stalks, or switchgrass."

The green logic is simple: Use carbohydrates to replace hydrocarbons. Farmers and the lumber industry generate copious amounts of cellulose-rich waste. America has lots of spare prairie, which grows grass. Gather the waste, harvest the grass and renewable biomass can replace dwindling supplies of crude. The global warming problem is solved, too, because plant growth pulls carbon out of the air.

In fact what lies ahead is an environmental debacle. Corn contains sugar, and sugars are easy to turn into ethanol. Just ask Anheuser-Busch or E. & J. Gallo. But to get a high-grade fuel out of wood, stalks or grass you have to take apart cellulose, a much tougher molecule. Some microbes and fungi can do it. So can cows, but only by filling their massive guts with those same microbes. And they do it inefficiently, and make quite a mess.

But the grass-to-fuel boosters don't plan to use cows. They plan to build chemical refineries that do the cow-gut thing much better. The key technical challenge is cheap production of huge quantities of robust, cellulose-splitting enzymes. Biochemists and genetic engineers could well find ways to deliver.

Plants won't celebrate if they do. (Consider, by way of analogy, how we humans might feel about a scheme to perfect flesh-eating bacteria, those mercifully rare strep bugs that digest muscles, fat and skin tissue with horrifying speed.) Plants pack their seeds with readily digestible sugar because they want animals to eat them. Most of the seeds get digested, but those that slip through get deposited, prefertilized, in some distant spot, where they grow another plant.

Cellulose, by contrast, is the adult plant's armor and scaffold. Voracious animals don't strip every last plant off the face of the earth only because most animals must work so hard to digest what plants are mostly made of.