Most trucks in the United States and many cars around the world have diesel engines. To make these vehicles greener involves replacing their current petrodiesel fuel with biodiesel. It only makes sense, considering that the inventor of the diesel engine, Rudolf Diesel, originally intended for them to run on fuels derived from vegetable oil.
Biodiesel is manufactured using vegetable oil (derived from corn, soybeans, peanuts, and other sources) that has been specially treated. All diesel engines are able to run on a fuel that is part petrodiesel, part biodiesel, as well as 100% biodiesel fuel (although it is known to cause problems in normal diesel engines in cold weather). Some vehicles, however, have special modifications that allow them use 100% pure biodiesel in any weather. It is best to ask the advice of an auto dealer when determining which type of fuel is best for the life of the engine
There are numerous benefits to using biodiesel. It keeps the fuel tank cleaner (this can also be a drawback; see below) as well as being free of fossil fuels. It has great potential as a “homegrown” energy source and therefore as a way to reduce dependence on foreign oil. It is also cleaner than diesel fuel; it produces less toxic chemicals then petrodiesel when burned in an auto engine.
In addition to the benefits, however, there are also some drawbacks. The countries currently producing the largest amount of biodiesel feedstock are in tropical regions and are growing oil palms; to do this they are clear-cutting and burning rainforest. Deforestation actually exacerbates global warming – we need trees to take carbon out of the atmosphere. Also, in terms of air pollution, gasoline-powered vehicles are much better than current diesel engines, which meet Tier 1 standards. Once Tier 2 standards are implemented, there will be more effective pollution control on diesel engines. There are also some engine performance issues. When biodiesel is used, it cleans out the fuel tank; there is therefore a risk that pieces of hardened fuel can become stuck in the fuel lines. Changing fuel filters frequently minimizes this risk. Also, in cold weather, biodiesel becomes denser and more difficult to pass through fuel lines. Installing a heater in the fuel tank is a good way of preventing problems in cold weather.
In addition to biodiesel, North Carolina State University is conducting research on renewable jet fuels made from vegetable oil. Once there are alternatives for jet fuel, more possibilities will open up for green travel and shipping.