From Grass to Gas: On the Road to Energy Independence, How Soon Will Cellulosic Ethanol Be a Factor?
Crooks, Anthony, Rural Cooperatives
Our nation used more than 140 billion gallons of gasoline last year and imported about 60 billion from the Middle East. The 4.3 billion gallons of fuel ethanol produced largely by our nation's farmers was a good start toward extending the nation's fuel supply, but really is just a baby step.
"America is addicted to oil," President Bush stressed in his State of the Union Address, during which he outlined the Advanced Energy Initiative (AEI) to address this serious problem. "We will increase our research in better batteries for hybrid and electric cars, and in pollution-free cars that run on hydrogen. We'll also fund additional research in cutting-edge methods of producing ethanol, not just from corn, but from wood chips and stalks, or switchgrass. Our goal is to make this new kind of ethanol practical and competitive within six years." For more on the AEI, visit: http://www. whitehouse.gov/news/releases/2006/05/20060524-4.html.
Speaking at a Senate Foreign Relations Committee meeting in June, former Federal Reserve Chairman Alan Greenspan said: "Corn ethanol, though valuable, can play only a limited role, because its ability to displace gasoline is modest at best. But cellulosic ethanol, should it fulfill its promise, would help to wean us off our petroleum dependence."
Advocates of cellulosic ethanol have been saying its day would arrive "within the next five years" since the mid-1990s. But this time they just may be right. They too were encouraged by President Bush's remarks. And while everything turns on oil prices, rising oil prices encourage new technologies by making them economical--including, perhaps, cellulosic ethanol within five or six years.
Is industry heading to cellulose?
Cellulosic ethanol is fuel ethanol made from cellulose, the inedible fiber that forms the stems and branches of plants. As the main component of plant cell walls, cellulose is the most common organic compound on earth. Crop residue (corn stover, wheat straw and rice straw), wood waste, and even municipal solid waste are sources of cellulose. High-biomass dedicated energy crops--think of President Bush's reference to switchgrass in his State of the Union Address--are also promising cellulose sources that can be produced in many regions of the United States.
Switchgrass is noteworthy for ethanol production because of its potential for high fuel yields, hardiness and ability to be grown in diverse areas. Trials show current average yields to be about five dry tons per acre. However, crop experts say that progressively applied breeding techniques could more than double that yield. Its long root system helps to make switchgrass drought-tolerant, growing well even on marginal land, and it requires little to no fertilizing. Its expected ethanol yield ranges from 60 to 140 gallons per ton; with typical yields in the 80-to-90 gallon range.
The potential energy from cellulosic ethanol is significant. A recent study estimates that a gallon of ethanol produced from corn provides about 20,000 Btu (British thermal units) more energy than the energy that went into making it. The net gain from cellulose, however, from a crop such as switchgrass, which doesn't require fertilizer, irrigation, or other energy-intensive activities, is triple that of corn, about 60,000 Btu per gallon. Not only that, but an acre of land planted in switchgrass can produce four times the cellulosic material as can land planted to corn.
Cellulose is among the most undervalued and underused energy assets in the United States. The Natural Resources Defense Council recently reported that by 2030, cellulosic ethanol could supply half of U.S. transportation fuel needs without reducing food and animal feed production.
Moreover, the unrealized potential of industrial biotech, completely apart from ethanol, is astonishing. Once plant sugars become abundantly available, any number of substances that now contribute to our "oil addiction" may be replaced with sugar molecules. …