Editor's note: The chart in Sierra's print version stated that vehicles using B99/100 biodiesel require special modifications. Unless the car is using 100 percent waste vegetable oil, the only modification necessary is to replace natural rubber fuel hoses on older vehicles. Modern diesel vehicles can use biodiesel with no modifications. The chart has been corrected.
IN OUR BEAUTIFUL BIOFUEL FUTURE, cars and trucks are powered by wood chips, prairie grass, wheat straw, fast-food grease, garbage, and even algae--whichever material is most plentiful locally and least damaging environmentally. With cars getting 40 miles a gallon or better, greenhouse-gas emissions plummet. The biofuel revolution sparks an economic boom by keeping U.S. dollars at home instead of sending them to Middle Eastern sheikhs.
Biofuels can be made from nearly any organic material. By essentially recycling carbon from living things (as opposed to the ancient biomass in coal and petroleum), biofuels help fight global warming. But some could also add to our environmental problems: In an equally possible but less rosy future, governments and agribusiness clear rainforests and wetlands for vast plantations of biofuel crops like oil palms. With arable land increasingly devoted to fuel production, food prices push higher. The roads clog with biofuel SUVs that still get lousy mileage. Global warming slows insignificantly, if at all.
Which future is ours? It depends on choices being made today. At present, for example, corn is the source of 95 percent of the United States' ethanol. Although politically popular in farm states, corn is a problematic source of fuel: It requires good land and petroleum-intensive cultivation and fertilization, and it can also readily feed both humans and livestock. (Food prices are already increasing because of competition with ethanol.) If the mill processing the corn is powered by coal, ethanol produces more net greenhouse gases than gasoline does.
"It's easier to do bad than good in this area," warns Dan Kammen, founding director of the Renewable and Appropriate Energy Laboratory at the University of California at Berkeley. "But there's also potential to make the production of fuel more decentralized and more democratic." The chart below lays out the pros and cons of the major biofuels; now it's up to us to get the right mix.
California governor Arnold Schwarzenegger (R) has boosted bioenergy by ordering that the carbon content of all fuels sold in the state be cut by 10 percent by 2020. Each fuel will get a life-cycle carbon analysis, showing how much greenhouse gas it emits from origin to tailpipe. Fuel suppliers will need to blend ingredients to meet their reduction targets, which should increase demand for cleaner options like cellulosic ethanol.
The Urge to Splurge
Putting a dent in global warming requires conservation as well as biofuels. A 3 percent increase in fuel-economy standards for vehicles, for example, would save more gas than the entire 2006 production of corn ethanol. Sadly, we've been driving in reverse: For the past five years, U.S. gasoline consumption has increased by 1.4 percent annually, and diesel by 3.6 percent.
Conserving Critters Too
The rush to biofuels is putting the squeeze on wildlife. Nearly 40 million acres of farmland are currently idled under the federal Conservation Reserve Program, which seeks to reduce soil erosion, improve water quality, and provide habitat. The Bush administration has proposed that land set aside under the program be converted to fuel production. The proposal is part of the 2007 Farm Bill, which is likely to be voted on this fall.
The best sources of biomass for fuel are waste products and native perennial grasses, which provide more usable energy per acre than corn ethanol or soybean diesel. In fact, says a report by the University of Minnesota, fuels made from native plants can actually be "carbon negative," because they store excess carbon dioxide in their roots and the surrounding soil, reducing the amount of CO2 in the atmosphere.
Crying in Your Biodiesel
Here's where some get off the biofuel bus: It's raising the price of beer. In Germany, subsidies for corn and rapeseed production are squeezing production of barley--an important ingredient in the national beverage. The effects of higher barley prices are starting to appear at the tap. The price of a liter mug of beer at this year's Oktoberfest, for example, will be up by 5.5 percent.
Illustrations (see chart) by Peter Hoey; used with permission.