Also known as agrofuel, biofuels are mainly derived from biomass or bio waste. These fuels can be used for any purpose, but the main use is in the transportation sector. Most vehicles require fuels which provide high power and are dense so that storage is easier. These engines require fuels that are clean and are in the liquid form.
The most important advantage of using liquid as fuel is that it can be easily pumped and can also be handled easily. This is the main reason why almost all vehicles use liquid form of fuels for combustion purpose.
For other forms of non transportation applications there are other alternative solid biomass fuels, such as wood. These non transportation applications can bring into use these solid biomass fuels as they can easily bear the low power density of external combustion. The use of wood as a fuel is one of the major contributors of global warming.
Biofuels are the best way of reducing the emission of the greenhouse gases. They can also be looked upon as a way of energy security which stands as an alternative to fossil fuels that are limited in availability. Today, the use of biofuels has expanded throughout the globe. Some of the major producers and users of biogases are Asia, Europe and America.
Theoretically, biofuel can be easily produced through any carbon source; making the photosynthetic plants the most commonly used material for production. Almost all types of materials derived from plants are used for manufacturing biogas. One of the greatest problems that is being faced by the researchers in the field is how to convert the biomass energy into the liquid fuel.
There are two methods currently used to solve the above problem. In the first one, sugar crops or starch are grown and, through the process of fermentation, ethanol is produced. In the second method, plants are grown that naturally produce oil, such as jatropha and algae. These oils are heated to reduce their viscosity, after which they are directly used as fuel for diesel engines. This oil can be further treated to produce biodiesel, which can be used for various purposes.
Biomass can be termed as material which is derived from recently living organism. Most of the biomass is obtained from plants and animals and also include their byproducts. The most important feature of biomass is that they are from renewable sources of energy, unlike other natural resources like coal, petroleum and even nuclear fuel.
Some of the agricultural products that are specially grown for the production of biofuels are switchgrass, soybeans and corn in the United States. Brazil produces sugar cane, Europe produces sugar beet and wheat, while China produces cassava and sorghum, south-east Asia produces miscanthus and palm oil and India produces jatropha.
However, two new studies call into question the global movement toward biofuel. According to researchers in the USA, production of biofuel actually contributes to global warming, doing more harm than good.
The studies, one conducted by Minnesota based Nature Conservancy and one by Princeton University, examined the same issue: What environmental impact does growing vegetation used for biofuel have on global warming?
U.S. demand for ethanol crops like corn, soy and switchgrass has resulted in the conversion across the globe of natural habitats, like grasslands and rainforests, into fuel-ready farmland, according to the studies. That development has released mass amounts of carbon into the air, researchers said.
Joe Fargione, the regional science director for the Nature Conservancy said "You ask the world's farmers to produce energy and that's going to take additional land.
That land has to come from somewhere. Unfortunately, much of it is coming from our natural ecosystem. What's the consequence of that? If you imagine a grassland and a cornfield, there's much more carbon in the grassland soil. When you convert a grassland into a cornfield, that carbon has to go somewhere. It goes into the air as carbon dioxide and contributes to global warming. Any biofuel that causes the clearing of natural ecosystems will increase global warming."
In the Princeton study, which was led by Timothy Searchinger, a German Marshall Fund fellow and a researcher at Princeton University, numbers told a striking story.
Using models that calculated carbon emissions in various countries, the Princeton researchers found that the production of corn-based ethanol nearly doubles greenhouse emissions over 30 years and increases greenhouse gasses for 167 years. Similarly, biofuels made from switchgrass, if grown on land originally intended for corn, increase carbon emissions by 50 percent.
Source: biofuel.org.uk and ABC News