AP Photo/The Canadian Press, Frank Gunn
DCL
Biodiesel is a clean-burning, petroleum-free alternative to conventional diesel fuel. It's made by chemically reacting a vegetable-based (or animal fat-based) fat with an alcohol, and can be used in standard diesel engines, either alone or mixed with petroleum-based diesel.
And not only does it burn cleaner, but because biodiesel can be made from food wastes like used vegetable oils, it's a great way to divert waste from the landfill. As seen in this COOLFUEL episode, soybean oil is a great source for biodiesel, and in fact was found to be more efficient and cleaner than corn-based ethanol. A study in Minnesota found that soy-based biodiesel not only brought a 93 percent return on the energy investment used in production, but also reduced emissions from conventional diesel fuel by 41 percent, compared with a 12 percent reduction from ethanol.
For try-it-at-home users, a quick note: make sure to get your biodiesel from a reliable source. The COOLFUEL crew may be a little more daring, but they can be because they know what they're doing. But if you want to put biodiesel into your own vehicle, be sure to purchase one that meets industry standards--they do exist and if you ignore them, you can ruin your engine. To meet industry specifications, soybean oil is combined with alcohol and a catalyst to undergo a process called transesterification. The mixture will separate into two parts: an alcohol-glycerol layer that will sink to the bottom, and an ester that will rise to the top--this becomes the biodiesel and after several washings, can be marketed as a fuel.
One of the largest hurdles to putting biodiesel into practice has been that in cold weather, it solidifies and clogs the fuel tank, but earlier this year, Indiana scientists drove from Anchorage to Fairbanks to test a new soybean-based biodiesel that was made with urea and separated the saturated and unsaturated fats. They successfully showed that when processed right, biodiesel can work in the cold, too.
Check out other kinds of alternative fuels, and watch the COOLFUEL crew travel from Oregon to the Canadian border on soybeans.
