In order to produce cellulosic ethanol all you need is a plant. The structural material a plant creates to support itself is cellulose, which is essentially a complex sugar. Using enzymes to break down the plant's cell walls into sugars then fermenting the sugars is the extremely basic explanation for how cellulosic ethanol is made.
The primary reason starch-based (corn and sugar cane) ethanol is easier is that the corn seeds are already fairly simple sugars and the methods to turn them into fermentable sugar is much simpler and cheaper.
But corn-based ethanol can only utilize the seed of the corn plant. Cellulosic ethanol can utilize the entire plant.
Interestingly, some of the most ideal plants for cellulosic ethanol are grasses, which have a high ratio of cellulose to mass. And they're cheap.
Here's my list of reasons that this is awesome:
1. CO2 emissions from the fermentation process are much less for cellulosic ethanol than for corn-based ethanol.
2. Tillage of soil to plant corn crops release large amounts of CO2 trapped in the soil, and switchgrasses are perennial, which means once planted tillage never need happen again.
3. Native species can be used. Why plant some genetically engineered freak corn when you could get ethanol from all-natural native plants that restore the native habitat.
4. Grass farming is much cheaper and easier than corn farming, and grasses (especially native) are far more resistant to local weather conditions. Also, many insects that wreak havoc on corn crops have no effect on grass.
5. Corn farming causes soil erosion. Grass farming actually decreases soil erosion.
6. With an abundance of native grassland areas, the government could reduce or end the CRP management policy, saving the tax-payers billions. (34,500,000 acres at 170 bucks an acre = 5,8 billion dollars a year.)
7. Mathematically, we could actually end our use of petroleum based fuel. Switchgrass production, at peak, could eventually produce enough oil to fuel the current U.S. fuel consumption. In 2007 fuel use actually dropped. Even better!
8. Corn-farming is creating a condition where there is a total lack of genetic diversity amongst all plants. If a bacteria or virus started wiping out corn, it could take out all corn because little or none of it would be virus-resistant. Switchgrasses could be planted in a mixed bag (read: hundres) of various native grass species, and when one grass suffered from illness, the other species could easily fill the void.
So I'm excited to see the Dems jumping on the cellulosic bandwagon. Although I don't agree with ethanol mandates and ethanol subsidies, this rests entirely on the fact that corn-based ethanol benefits literally no one except corporate corn farmers.
Cellulosic ethanol could free us from foreign oil, decrease CO2 emissions, increase U.S. wealth, increase native populations, and decrease fertilizer and genetic engineered crop use.
But the main reason I love this is that normally technology and cars and fuel clash violently with the natural world. Here's a solution to the fuel crisis that involves cutting-edge technology - that actually encourages returning farmland to native plant growth. Imagine a shining ethanol plant, sitting in a field, surrounded by thousands of acres of tall-grass prairie. Now that is what I call harmony.
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