http://www.energybulletin.net/19214.htmlEnglish ecologist Jeffrey Dukes calculated in 2003 that it takes 98 tons of prehistoric, buried fossilized plant material to produce each gallon of fossil fuel that we burn in our cars.1 98 tons to the gallon is poor mileage even by SUV standards. Dukes also calculated that the amount of hydrocarbons burned in fossil fuels each day was equal to the amount of carbon sequestered by all of the plants on earth every year. These measurements hint at the challenges human society will face if it tries to replace fossil fuels with biofuels.
What are biofuels? Briefly, they are liquid fuels made out of recently living organisms, predominantly plants. The primary biofuels are ethanol (made from plant sugars), cellulosic ethanol (made from wood and other plant fibers) and biodiesel (from plant-derived fats and oils). The most common source plants for ethanol are sugarcane, sugar beets and corn. Cellulosic ethanol can be made from wood and fast-growing plants like grass (especially switchgrass). Biodiesel is commonly produced from soybeans (in mid-latitudes) and palm oil trees (in the tropics).
Can biofuels be produced from plants that will run vehicles? Yes, they can. Can biofuels replace all or an appreciable part of the 85 million gallons of petroleum that the world consumes on a daily basis? No, they can’t. Here’s why.
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Biofuels could play a meaningful role in a society that lived with some ecological modesty. There is no real long-term option for us other than living by nature’s non-negotiable ecological rules. Nobody argues with gravity, why argue with the simple reality of a spherical, limited-in-all-directions planet? If we want our species and life in general to flourish, we will have to drive less, fly less (or not at all), buy less, build smaller homes, have smaller families, and relearn how to live local, community- and watershed-based lives.
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