As with most ideas for change there are positive and negative points that must be weighed in order to implement part or all of that idea. Biodiesel, fuel made from oils derived from plants, algae, fungi and bacteria, is one of those topics that requires careful analysis. At first glance, one might assume that biodiesel could be a major player in helping the United States become more independent on foreign oil. It may yet be, but there are important and costly things requiring consideration.
There are many types of plants that produce oils capable of being used as fuel in diesel engines of all types, jet engines and gas turbines. Yes, it is easier and more ecologically beneficial to make this fuel from plants than it is making ethanol from corn. The processing of biomass for biodiesel also produces a fuel that contains much more energy per volume than ethanol. BUT, pure biodiesel tends to destroy the gaskets and seals in traditional diesel engines. There are modern materials that are compatible with biodiesel, and most new diesel engines include these materials in their manufacture. Older engines would have to be re-fitted at some cost. Diluting biodiesel with ethanol and petro-diesel also ameliorates this problem.
However, even then if we adopt those older engines to the biodiesel, we are still going to make a nice change that will be worth it because we won’t be using the regular diesel or other types of fuel that are hurting the nature. That’s why we need to stay open to this idea.
The amount of arable land or seashore required to produce sufficient biodiesel to replace other, traditional motor fuels is enormous. State-sized rapeseed fields, for example, would be needed to produce enough biodiesel to replace just the amounts we use in our truck-based transportation of goods.
As with any major change involving new technology or innovation, cost-benefit studies determine the direction and pace of change. Right now, it costs about the same to create a gallon of biodiesel as it does petro-diesel. This does not include the environmental impact cost differences between the two fuel types because there is insufficient data. The data there is shows that fewer harmful chemicals of combustion are produced by biodiesel than from petro-diesel combustion due to the nature of the molecules in the two fuels.
The best conclusion today is that biodiesel is absolutely worth pursuing for a variety of reasons, not the least of which is creating production technologies that are more cost-effective than petro-diesel at different consumption levels. What I mean is that clearly, we cannot use vast tracks of our land (plants) or seashores (algae) to generate enough biodiesel to replace all petro-diesel use, never mind gasoline fuels. We can, however, consider certain areas for petro-diesel replacement, like ocean-going ships, home heating fuel, trains and local transportation like mail trucks. We simply use too much jet fuel and motor fuel (gasoline) right now for biodiesel to be a practical and economical replacement for all our fossil fuel needs.
There will come a time, however, when the cost curves will cross into the positive ranges due to increasing scarcity of petroleum, so we need to be ready to implement an intelligent plan of technology and production when biodiesel’s turn comes.