Ethanol and Biodiesel as Alternative Fuels

Biofuels are becoming important as alternative fuels in the fight against greenhouse gas emissions. They also help to cut down on the use of fossil fuels.

In the continuing battles on global warming and diminishing oil reserves, Biofuels are an essential weapon in the armory. Unlike other alternative fuels, biofuels force little or no changes in the modes of transport most used by consumers today. In addition, the technology used to create biofuels is tried and trusted, and the “bio” parts of the ingredients are renewable.

Biofuels can be defined as any combustible fuel derived from biomass, which is from living organisms or the waste from such organisms. Biofuels can also be produced to a lesser degree from waste products such as tires and waste cooking oil. In recent years, the term “biofuel” has primarily referred to ethanol, made from crops including corn and sugarcane, and biodiesel made from palm oil and rapeseed. Bioethanol, an alcohol, is usually mixed with petrol, while biodiesel is either used on its own or in a mixture.


The leading biofuel used as an additive to gasoline is ethanol. Ethanol for fuel is produced by corn, maize, wheat, sugar beet, and sugarcane crops. Ethanol is a clear, colorless liquid, which is biodegradable, low in toxicity, and causes little environmental pollution if spilled. In addition, ethanol is a high octane fuel and helps achieve more complete combustion, thus cutting down on emissions.

According to the US Department of Energy, around one-third of the gasoline sold in the United States includes 5% or 10% ethanol. Modern cars have no problem using this fuel, although some older models might need some modification. All new car warranties in the US cover the use of up to 10% ethanol. There is also a 20% mixture of ethanol and gasoline, but cars may need more modifications to use it, and users should check their warranties for cover. These fuels are known as E5, E10, and E20, depending on the amount of ethanol in them.

An even better alternative fuel is E85, an 85% ethanol and 15% gasoline mixture. According to the US Energy Information Administration, “vehicles are not modified to run on E85; they are specially manufactured as flexible fuel vehicles (FFV). Flexible Fuel Vehicles can use any mixture of ethanol and gasoline up to E85. There are about 146,000 cars and trucks using E85. Most of these are fleet vehicles.”


Biodiesel is a clean-burning alternative fuel made from straight vegetable oil, animal oil/fats, tallow, and waste cooking oil. The largest possible source of suitable oil comes from oil crops such as rapeseed, palm oil, or soybean. These oils must go thru a process called “transesterification” to produce biodiesel that meets the requirements of ASTM D 6751. Biodiesel contains no petroleum but can be used instead of diesel or blended with petroleum diesel as a fuel.

According to the US Department of Energy, “Biodiesel is most often blended with petroleum diesel in ratios of 2 percent (B2), 5 percent (B5), or 20 percent (B20). It can also be used as pure biodiesel (B100). Biodiesel fuels can be used in regular diesel vehicles without making any changes to the engines.”

B20 is used chiefly by vehicle fleets and school buses but is also available to individual users. According to the EPA, there are more than 300 fueling stations in about two-thirds of the states.

Biofuels such as ethanol and biodiesel play an ever-increasing role in the search for green energy and alternative fuels. They are considered renewable fuels as they are manufactured from plants, and although there are questions on biofuels effect on food production and they do produce Carbon Dioxide, a greenhouse gas, they tend to have less of the other dangerous pollutants, such as sulfur, that is common to fossil fuels.