Biofuel comes in a number of varieties, such as ethanol, biiodiesel, or methane, produced from renewable resources, especially plant biomass and treated municipal and industrial wastes.
Biofuels are considered neutral with respect to the emission of carbon dioxide because the carbon dioxide given off by burning them is balanced by the carbon dioxide absorbed by the plants that are grown to produce them. Depending on the method of production, biofuels can also be carbon negative. The use of biofuels as an additive to petroleum-based fuels can also result in cleaner burning with less emission of carbon monoxide and particulates.
There are several types of biofuels:
- Biodiesel: Made by processing vegetable oils, waste cooking oils, and other fats and is also used either in pure form or as an additive to petroleum-based diesel fuel. Biodiesel can also be made from alage and other non-traditional oily feedstocks.
- Biogas: A mixture of methane and carbon dioxide produced by the anaerobic decomposition of organic matter such as sewage and municipal wastes by bacteria. It is used especially in the generation of hot water and electricity.
- Ethanol: Produced by fermenting the sugars in biomass materials such as corn and agricultural/plant residues. Ethanol is used in internal-combustion engines either in pure form or more often as a gasoline additive. “E85” gasoline blend that is 85% ethanol and 15% gasoline is a popular fuel for some vehicles that have made an inexpensive conversion to accommodate the different fuel. “E10” which is also popular in some states requires no conversion and can be used in any vehicle.
- Cellulosic ethanol: While ethanol is typically produced from the starch contained in grains such as corn, it can also be produced from plant matter containing cellulose. Cellulose is the main component of plant cell walls and is the most common organic compound on earth. Cellulose is made up of starch and sugars that can be used to make ethanol—but first it must be broken down which can prove difficult. Yet, making ethanol from cellulose dramatically expands the types and amount of available material for ethanol production. This includes many materials now regarded as wastes requiring disposal, as well as corn stalks, rice straw and wood chips, or “energy crops” of fast-growing trees and grasses.Importantly, it offers tremendous opportunities for new jobs and economic growth inside and outside the traditional “grain belt,” with production across the country from locally available resources. Cellulose ethanol production will also provide additional greenhouse gas emissions reductions—in some cases, making ethanol produced in this fashion carbon negative.
Sources: Renewable Fuels Association and the American Heritage Science Dictionary, The Methane Digester for Biogas, National Biodiesel Board
- With a 113 octane rating, ethanol is the highest performance fuel on the market and keeps today’s high-compression engines running smoothly.
- Today nearly 50% of all gasoline in the U.S. is blended with ethanol.
- Ethanol-blended fuels are approved under the warranties of all auto manufacturers marketing vehicles in the U.S. Some even recommend ethanol use for its clean burning benefits.
- All mainstream manufacturers of power equipment, motorcycles, snowmobiles and outboard motors permit the use of ethanol blends in their products.
- The production cost for cellulosic ethanol is substantially less than food crop derived ethanol.
- Biodiesel has a higher cetane number than diesel fuel. In more than 50 million miles of in-field demonstrations, B20 showed similar fuel consumption, horsepower, torque, and haulage rates as conventional diesel fuel.
- The use of biodiesel in existing diesel engines does not void parts and materials workmanship warranties of any major US engine manufacturer.
- About 1.7 cubic metres of biogas equals one litre of gasoline. The manure produced by one cow in one year can be converted to methane which is the equivalent of over 200 litres of gasoline
Sources: Renewable Fuels Association and the American Heritage Science Dictionary, the Methane Digester for Biogas, the National Biodiesel Board.