What are Biofuels?
Biofuels are designed to replace gasoline, diesel fuel and coal, which are called “fossil fuels” because they are made from animals and plants that died millions of years ago. Biofuels are made mostly from plants that have just been harvested.
There are three main types of biofuel. Ethanol, biodiesel, and biojet fuel. Ethanol is used in engines that burn gasoline, like most cars. Biodiesel is used in engines that burn diesel fuel, like large trucks and tractors. Biojet fuel is used in planes.
Are Biofuels Renewable Energy?
To be renewable, an energy force must be able to be replenished easily and quickly and not have a finite limit. In other words, if it’s possible to run out of the energy source, then it is not renewable. Things like fossil fuels are not a renewable because they take so long to form that we could use all of them much faster than they could be replenished. Biofuels are considered renewable because they can be replenished as quickly as they are used. In other words, under normal circumstances we will not run out of energy derived from biofuels.
Are Biofuels Better for the Environment?
The jury is still out on this one. Some people say the biofuels are better because the carbon dioxide they produce is taken up when new biofuels crops are grown. So, there is no net increase in carbon dioxide, which is a greenhouse gas.
Other people point out that energy has to be invested into growing biofuels. For instance, land has to be plowed and fertilizer must be applied. When you take all of these factors into account, biofuels actually produce more carbon dioxide than fossil fuels. These people are worried that too much land will be cleared to produce biofuels, which will threaten habitat and cause some plants and animals to become extinct.
Right now, people are trying to figure out how to make biofuel production more efficient so that we get more energy out than we put into growing the crops. This should be possible because most of the energy comes from the sun, so if we cut down on how much preparation is involved, we might be able to ensure that biofuels environmentally friendly.
Are Biofuels Better for Air Quality?
For the most part, yes. Biofuels produce less particulate like smoke and soot. They also produce lower dangerous chemicals like sulfur, which is the leading cause of acid rain. Biofuels also produce less ozone, which is one of the primary components of smog.
Do Biofuels Use a Lot of Water?
Depending on the crop used to produce the biofuel, they use anywhere from 2 to 84 times as much water as fossil fuels. Scientists are currently working very hard to reduce the water needs of biofuels.
Do Biofuels Threaten the Food Supply?
This is another tough one. The short answer is yes. Anytime that food crops are not grown because biofuel crops are being grown, there is a net reduction in the amount of food available. This has already caused a problem in some poor countries because the increased use of farmland for biofuel crops means that there is less land available for food crops and this drives up the price of food. In some countries, this has increased the price enough that some people cannot afford as much food.
If we can find a way to grow biofuel crops that is not used for food crops, then we will have solved the threat that biofuels pose to food. However, this may inadvertently increase the environmental impact of biofuels.
What is Ethanol?
Ethanol is another word for alcohol made from grains. It is the same alcohol that people drink and it can be produced from corn, barley, wheat, grass, sugar cane, and a number of other things.
Ethanol is often used as a biofuel. In most countries, it is mixed with gasoline to create a blend that is sometimes referred to as gasahol. In the United States, the mixture is usually 10 percent ethanol and 90 percent gasoline. This is referred to as E10 and it can be used in any car that burns gasoline. Some cars are known as flexible fuel vehicles or flex fuel for short. These cars can use gasoline that contains as much as 80 percent ethanol. In Brazil, some cars can run on 100 percent ethanol, which is widely available in that country thanks to its abundant supply of sugar cane.
What is Biodiesel?
Biodiesel is a term applied to any diesel fuel that is made by refining oil, fat, or grease collected from plants and animals. The most common oil used to produce a biodiesel is vegetable oil. Like gasoline, standard diesel fuel is often blended with a biodiesel. The most common blend is 20 percent biodiesel and 80 percent regular diesel. This blend is known as B20. Though B20 is most common, blends can range from 2 percent biodiesel all the way to 100 percent biodiesel.
How are Biofuels Made?
The method used for producing ethanol is different than the method used for producing a biodiesel. What they share in common is the first step for both is to grow the plant that will eventually be used to make the fuel.
For ethanol, once the plant (corn or sugar cane for instance) have been harvested, bacteria are allowed to digest it. When they do this under special conditions where oxygen levels are kept low, it is called fermentation. Fermentation produces ethanol.
For biodiesel, the process requires chemical reactions. There are several different chemical reactions that can be used to produce a biodiesel, the most common of which is called transesterification. This is just a fancy word to describe the process of breaking down fats in the presence of methanol (another type of alcohol).
What Kinds of Things can Biofuel be Made From?
The source used to make a biofuel is called a feedstock.
Ethanol can be made from any of the following feedstock:
- Sugar cane
- Sugar beet
- The inedible parts of most plants (the parts you can’t eat)
Biodiesel can be made from any of the following feedstock:
- Jatropha – A cactus-like plant
- Camelina – A flowering plant
- Rapeseed – A kind of seed
- Canola Oil
- Palm Oil
- Peanut Oil
- Vegetable Oil
- Animal Fat
- Algae oil – Oil made by algae that live in water
How much Biofuel is Made Each Year?
About 25 billion gallons of ethanol are made each year for use as fuel. About 1 billion gallons of biodiesel are produced each year.