Biodiesel and ethanol are both biofuels: fuels produced from organic matter. As global warming worsens and our oil supply dwindles, biodiesel and ethanol have both been touted as the fuels of the future. They are purported to be renewable, and clean.

Because these similarities, people frequently confuse ethanol with biodiesel, and vice versa. Ethanol and biodiesel are completely different substances, with completely different properties. For one, ethanol is an alcohol. It is the alcohol found in beer, wine, vodka, etc.

If you drank biodiesel, on the other hand, you would most likely suffer harm. Biodiesel is an ester: a substance composed of an alcohol bonded with a fatty acid. The alcohol is usually ethanol, or methanol, also known as wood alcohol. The fatty acid is obtained from animal fats or plant oils.

So how is ethanol, the fuel, made? The same way that drinking alcohol is made: fermentation. Farmers grow high sugar or high starch crops, such as sugar cane. The sugar cane is juiced, and the juice is allowed to ferment. The alcohol is then purified.

Biodiesel is also made from plant matter. However, instead of sugary plants, crops with high oil content are favoured, such as rapeseed, palm trees, and corn. The crops are harvested and their oil extracted. The oil is then reacted with ethanol or methanol, to produce biodiesel.

The processes above describe making ethanol and biodiesel from new raw materials, as opposed to waste matter. It is possible to make both ethanol and biodiesel from waste. Compost can be fermented and ethanol extracted. Instead of using fresh oil, biodiesel manufacturers sometimes use waste oil from fast food restaurants.

If you live in a major city in North America, chances are 15% of the fuel you receive at the gas station is ethanol. The 15-85 mixture of alcohol and standard gasoline, lovingly nicknamed gasohol, has become the convention. It can run in any normal gasoline engine, with no modifications required.

Biodiesel cannot be used with a gasoline engine. It requires a diesel engine—any conventional diesel engine. Before switching over to biodiesel, however, ensure that your fuel lines are not made from natural rubber. Biodiesel will simply dissolve the hosing.

Engines in North America are predominantly gasoline-oriented. For this reason, gasoline pumps are much more popular than diesel pumps in North America. To use ethanol for your car, you simply need to visit your local gas station. To find biodiesel, however, you need to look around. Currently biodiesel is not mass produced in either Canada or the United States. Infrastructure for the transportation of biodiesel is not widespread. Awareness and demand for biodiesel is also low.

Consequently, you may need to travel a few miles before you can find a biodiesel station. Even then, the cost per litre is 250% that of gasohol. The low demand and its high price lead each other around in a vicious cycle. Which one is better for the environment? That is debatable. Both are renewable energy sources that come from organic matter. For this reason, their advantages and drawbacks are quite similar. In the end, however, ethanol is just easier to find.

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