It didn’t take long for biofuels to turn from environmental cause célèbre to bête noire. Can second generation biofuels rectify the balance between food and fuel?
 | Fuel of the Future?A worker shows a handful of corn at the GreenField Ethanol plant in Ontario, Canada (Photo: Reuters) |
The most established alternative fuels for transportation are biofuels, primarily corn- and sugar-based ethanol and biodiesel derived from soybeans, palm, and other plant oils. These are usually blended with conventional gasoline or diesel. The attraction is that the carbon dioxide produced by burning biofuels was already present in the air before plants sucked it up and so there is no adverse impact on the climate.
Research firm Global Insight predicts that by 2030, more than 100 billion gallons of biofuels will be produced globally, enough for about 15 percent of the world’s motoring fuel needs.
Corn-based ethanol has made headlines in the United States as a possible alternative to imported petroleum. Even the racecars of the Indianapolis 500 use it. However, the UN Intergovernmental Panel on Climate Change concludes that the climate benefits are “minor” because corn farming and processing are so energy intensive. Most ethanol plants burn natural gas or coal to help distill the fermenting corn.
Furthermore, the conversion of cornfields from food production to fuel production contributes to global food shortages and increased food prices, say critics. A more prosaic problem is that, as Henry Ford discovered, corn ethanol delivers only two thirds the energy of gasoline.
Sugar cane ethanol, pioneered in Brazil, is greener, cheaper, and more powerful, generating over eight times more energy than is used in its production, compared with 1.5 times for corn ethanol. It also yields twice as much ethanol per hectare of farmland. Ninety percent of new Brazilian cars can run on any mixture of gasoline and ethanol. Brazilian ethanol has its detractors, however, who argue that the industry destroys rainforests, a vital carbon sink.
The biofuels backlash has led the European Parliament's industry committee to reduce the ten-percent target for use of traditional biofuels in road transport by 2020, calling for the use of alternatives like electricity, hydrogen, or second-generation biofuels.
Second-generation biofuels extract plant cellulose from non-food crops like grasses, waste wood, and even algae. Some of these plants boast higher yields than traditional biofuels, and they require less energy to cultivate.
The U.S. government suggests that 1.3 billion tons of plant matter could be collected from American soil without affecting food production. This could be converted into the ethanol equivalent of 350 billion liters of gasoline, or 65 percent of the country's current annual gas consumption.
In India, both jatropha and pongamia seeds yield oils that can be made into biodiesel, and so reduce dependence on edible crops like canola, palm oil, and soybeans. These hardy plants can grow on dry, stony ground, and so need not compete for fertile land and water with food crops. However, jatropha and pongamia plants take years to mature and bear fruit.
Not so with algae, which can be harvested daily due to their phenomenal growth rate. Scientists around the world are feeding pond scum with sunlight, wastewater, and carbon dioxide from power plant effluent in an accelerated form of photosynthesis that doubles as a method of carbon capture. The resulting crop is potentially explosive, containing 20 to 70 times more oil content than other biodiesel crops. One company claims that while an acre of corn can produce 300 gallons of ethanol a year, an acre of algae could theoretically produce 5,000 gallons of biofuel annually.
editor: James Tulloch
publishing date: September 29, 2008
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