Diesel and biodiesel are two products that can perform the same function, but come from very different sources. Both diesel and biodiesel can be used to fuel diesel vehicles, such as cars, trucks, tractors, and powered lawn mowers. The major different between these two fuel sources is that diesel comes petroleum, a non-renewable fossil fuel byproducts, whereas biodiesel is extracted from plant, seed, and animal oils. Diesel and biodiesel also vary in availability; while diesel is usually a standard product at most gas stations, biodiesel suppliers are often few and far between.
Diesel engines were originally created to be a more-efficient product than gasoline engines. Diesel, which is more oily and thick than gasoline, requires less refining than gasoline and is also generally less expensive. Popularized by the trucking industry, diesel is often favored over gasoline for large vehicles that carry heavy loads.
Though somewhat more efficient than gasoline, the primary downside to traditional diesel is its effect on the environment. In the burning process, diesel emits high levels of soot and nitrogen, which translate into increased air pollution, smog, and high concentrations of acid in rainwater. In addition, like gasoline, diesel also releases greenhouse gasses, such as carbon monoxide, which may contribute to global warming and ozone damage. One other issue with traditional diesel is that it comes from a non-renewable source, petroleum, which means that overuse can lead to depletion or even total annihilation of natural resources. Though the greenhouse emissions are lower than those given off by gasoline, many environmental experts consider diesel a serious threat to air quality and the environment.
Biodiesel is a renewable from of diesel made out of biodegradable oils, such as soybean or peanut oil. When combined with certain alcohols, the fat in these oils create long chains of a chemical substance known as esters, which make the oil usable as a fuel. Biodiesel can be used in nearly any diesel engine with few modifications and no damage to the engine. In addition to coming from a renewable source, biodiesel releases extremely marginal levels of pollutants into the air.
In comparing diesel and biodiesel, it is easy to assume that diesel is evil and biodiesel a miraculous, safe-for-the-environment product. In fact, diesel was originally created to improve engine efficiency, thus cutting down on wasted fuel. Biodiesel, while having many advantages in terms of reducing pollution, requires the diversion of food crops into oil production. In developing nations, some worry that the crop diversion needed to make biodiesel and other biofuels could lead to decreased food supply and increased levels of starvation. While neither diesel nor biodiesel do not seem to hold perfect answers for the future of fuel, both are important steps on the long path toward clean, renewable, efficient sources of energy for transportation.