Biofuels flop in efficiency, but technology moves forward

With an oil-drenched Gulf, record temperatures and tightened belts on nearly everyone's mind, alternative energy sources are looking increasingly attractive. Biofuels are nothing new. Prior to the advent of gasoline, many people believed vegetable oil would be the main fuel source in automobiles. Oil won out, however, and biofuel technology will need to make longer strides before it becomes a viable source of power.

Some biofuels actually cause more damage than fossil fuels, say scientists at the Smithsonian Tropical Research Institute. The mass production of crops such as corn and palm oil results in environmental destruction, pollution and damage to human health. The study identified the best biofuels as those coming from residual products such as recycled cooking oil. A hardy plant called jatropha is becoming popular as a source of biodiesel because it can be grown in semi-arid regions where other crops don't survive. The plant's seeds contain large amounts of oil that have already been successfully tested in jet fuel. It is still unknown what effect its widespread cultivation would have on the environment.

One of the most significant drawbacks of biofuels is the large amount of land and water needed to cultivate the crops to meet our energy needs. Converting crops to ethanol essentially takes food from our mouths to put fuel in our cars. According to the International Water Management Institute (IWMI), it takes approximately 2,400 liters of water to yield one liter of ethanol. The organization argues that growing biofuels will aggravate the fierce competition between businesses, farmers and domestic users in water-scarce areas. IWMI recommends focusing on less thirsty plants that won't compete with food crops.

More efficient methods of producing biofuels can help reduce their waste stream. Most of a plant's energy is housed in its woody, protective exterior and breaking down this coating is the first step in creating a biofuel. Typically plant matter is treated with harsh chemicals to break down this coating, and then exposed to enzymes that turn its carbohydrates into sugars which are fermented into ethanol. A large portion of carbohydrates is lost in a liquid waste stream. Researchers at North Carolina State University have found a better way to extract the carbohydrates from woody plants like switchgrass and inedible corn stalks. Instead of using chemicals, they exposed the plant matter to gaseous ozone and produce a carbohydrate-rich solid with little liquid waste. Researchers note that the process is more expensive than a chemical bath, but is ultimately more cost-effective due to its efficient use of plant matter.

Biofuels certainly have the potential to be greener than petroleum. They are renewable, cleaner and safer to handle than oil-based fuels. Biodiesel, for example, has a flash point between 200 and 300 degrees Fahrenheit, which means it is less likely to ignite than conventional fuels. The flipside is that biodiesel also has a high "cloud point" or point at which wax crystals form. The fuel becomes gel-like at freezing temperatures and can then clog a vehicle's filters and fuel lines. This makes biodiesel unreliable in winter weather, unless kept warm or mixed with appropriate amounts of kerosene.

Earlier this year, the U.S. Navy tested a blend of regular and biofuel in a fighter jeb dubbed the "Green Hornet." The jet flew for 45 minutes using a 50/50 blend of conventional jet fuel and camelina-based biofuel. The flight test confirmed that the biofuel blend performed just well as conventional fuel in operation of the aircraft even at sonic speeds. There is still some concern than using biodiesel in older engines will clog filters due to its solvent effect on existing deposits in pipes and tank walls, and it comes with a lower fuel economy than gasoline. Scientists with the National Renewable Energy Laboratory continue to strive for more stable, higher quality biofuels. With the backing of the military, as so often happens with new technologies, biofuels may eventually become cheap enough and reliable enough for the average person to pull into a gas station and fill up with fuel made from algae or jatropha. For the time being, converting your car to run on biodiesel remains an expensive,  hands-on project.