A biofuel is a fuel that is prodoced through contemporary biological processes

A biofuel is a fuel that is prodoced through contemporary biological processes, such as agriculture and anerobic respiration, rather than a fuel produced by geological processes such as those involved in the formation of normal fossil fuel, such as coal and petroleum, from prehistoric biological matter,which were inside the earth for millions of years.

Biofuels can be extracted directly from plants (energy crops), or indirectly from agricultural, commercial , domestic, or industrial wastes. Renewable biofuels normally involve contemporary carbon fixation, such as those which occur in plants or algae by the process of photosynthesis . Other renewable biofuels are made from the use or conversion of biomass (referring to recently living organisms, and most often referring to plants or plant-derived materials). This biomass can be then converted to convenient energy-storing substances in 3 different ways,i.e. thermal conversion, chemical conversion, and biochemical conversion. This biomass conversion can produce fuel in either of solid,liquid or gas form. The new biomass can also be sometimes used directly as biofuels.

Biofuels are in theory considered carbon neutral, because the carbon dioxide that is absorbed by the plants for photosynthesis is equal to the carbon dioxide that is released when the fuel is burned. However, in practice, whether or not a biofuel is carbon-neutral depends greatly on whether the land which is used to grow and produce the biofuel (with 1st and 2nd generation biofuel) was cleared for the same purpose or not.

Bioethanol is an alcohol produced by fermentation, mostly from carbohydrates present in sugar or starch crops such as corn, sugarcane or sweet sorghum. Cellulosic biomass, derived from non-food sources like trees and grasses, is also being developed now as a feedstock for the ethanol production. Ethanol can be used as fuel for automobiles in its pure form (E100), but it is usually used as a gasoline additive to increase the octane ratio and improve the vehicle emissions. Bioethanol is widely used in the United States of America and in Brazil. But for most countries, current plant designs does not provide for converting the lignin portion of plant raw materials to fuel components easily by fermentation.

Biodiesel can be used as a fuel for automobiles in its pure form (B100), but it is usually used as a diesel additive to reduce levels of particulateslike carbon monoxide and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and it is the most common biofuel being used in Europe.
In 2010, worldwide biofuel production reached over 105 billion liters (28 billion gallons US), up 17% from 2009, and biofuels provided 2.7% of the world’s total fuels for road transport. Globally, ethanol fuel production reached 86 billion liters (23 billion gallons US) in 2010, with the United States of America and Brazil as the world’s top producers again, accounting together for about 90% of the total global production. The world’s largest biodiesel producer is the European Union (EU), accounting for about 53% of all biodiesel production in 2010. As of 2011, mandates for blending biofuels is present in 31 countries at the national level and in 29 states or provinces.The International Energy Agency has a goal for biofuels to meet more than a quarter of the world demand for transportation or automobile fuels by 2050 to reduce dependence on petroleum and coal. The production of biofuels has also led into a flourishing automotive industry, where by 2010, 79% of all cars produced in Brazil were made with a hybrid fuel system of bioethanol and gasoline which is really a great step towards promoting biofuels.

First-generation biofuels-
“First-generation” or conventional biofuels are biofuels produced from food crops grown on arable land. by this biofuel production generation, food crops are then thus explicitly grown for fuel production, and not anything else. The sugar, starch, or the vegetable oil obtained from the crops is then converted into biodiesel or ethanol, using transesterification, or yeast fermentation.
Second-generation biofuels

Second generation biofuels are fuels manufactured from various different types of biomass. Biomass is a wide-ranging term meaning any source of organic carbon containing compound that is renewed rapidly as part of the carbon cycle. Biomass is normally derived from plant materials, but can also include animal products.
While first generation biofuels are made from the sugars and vegetable oils found in arable crops, second generation biofuels are produced from lignocellulosic biomass or woody crops, agricultural residues or waste plant products (from food crops that have already fulfilled their food purposes) The feedstock used to generate second-

generation biofuels thus either grow on arable lands, but are just by-products of the actual harvest (main crop) or they are grown on lands which can’t be used to effectively grow food crops and in some cases neither extra water or fertilizer is applied or given to them. Non-human food, 2nd generation feedstock sources include grasses, jatropha and other seed -crops, waste vegetable oil, municipal solid waste and so forth .
This has both advantages and disadvantages as well. The advantage is that, unlike with the regular food crops, no arable land is used solely for the production of biofuel. The disadvantage is that unlike with regular food crops, it can be rather difficult to extract the fuel. For instance, a series of physical and chemical treatments and processes might be required to convert lignocellulosic biomass to liquid fuels suitable for the transportation .

Third-generation biofuels
From 1978 to 1996, the US NREL experimented with using the algae as a biofuel source in the ‘Aquatic Species Program’. In a self-published article by Michael Briggs, at the UNH Biofuels Group, it offers estimates for the realistic replacement of all vehicular fuel with biofuels by using algae who have a natural oil content greater than 50% in them, which Briggs suggests can be grown in algae ponds at wastewater treatment plants.This oil-rich algae can be then extracted from the system and processed into biofuels, with the dried remainder by-product also being further reprocessed to create ethanol. The production of algae to harvest oil for producing biofuels has not yet been undertaken on a commercial scale, but feasiblity studies have been conducted to arrive at the above yield estimate. In addition to its projected very high yield, algaculture – unlike crop based biofuels – does not entail in a decrease in food production, since it requires neither of farmland or fresh water. Many companies are pursuing algae bioreactors for various research purposes, including scaling up biofuels production to the commercial levels. Prof. Rodrigo E. Teixeirafrom ,from the University of Alabama in Huntsville state demonstrated the extraction of biofuels lipids from wet algae using a very simple and economical reaction in ionic liquids.
Fourth-generation biofuels
Similarly to the third-generation biofuels, fourth-generation biofuels are also made using non-arable land. However ,unlike third-generation biofuels, they don’t even require the destruction of biomass. This class of biofuels include electrofuels and photobiological solar fuels. Some of these fuels are carbon-neutral..


Brazil is the current global leader in the use and production of ethanol as a fuel source. An examination of the history of Brazil’s sugarcane ethanol industry can easily provide valuable insight into the factors that contribute to the great success of a large-scale biofuel program. Countries that are looking into increasing their biofuel use in order to become less dependent on petroleum-based fuels should learn from the success stories of countries like that Brazil. Of course, even Brazil’s relatively successful ethanol industry has had its fair share of setbacks once,every one has,but it overcame it. Understanding the obstacles faced by this well-established industry will be very usefulforothers in determining how future biofuel industries can be even more efficient and successful.

Though alcohol can be fermented from almost any plant or plant product, the efficiency, energy yield and environmental effects of the fermentation process vary drastically depending on the plant. Ethanol in Brazil is primarily produced from sugarcane, which is currently at present considered one of the most efficient feedstocks for biofuel production. This efficiency is largely a result of using the sugar cane bagasse (the fibrous residue leftover after the juice is extracted from the sugarcane) to power the process. There are like quite a few advantages to supplementing petroleum with biofuels such as sugarcane ethanol. Petroleum is more toxic and more dangerous and produces more threatening pollutants than ethanol. It is also more likely to cause explosion impact the environment negatively if spilled. However, there are also few disadvantages associated with ethanol fuels. For example, they corrode engines more easily and provide less energy per unit volume than petroleum. Despite these drawbacks, the government of Brazil has provided and continues to provide strong and firm support for the production, use and distribution of sugarcane ethanol.
Brazil’s ethanol industry has a very long history beginning in the 1930s when the Brazilian government ordered that the ethanol to be blended into all gasoline in a 5-to-100 proportion. This proportion almost increased to 40% in certain parts of the country during and directly following World War II. At this time, the government also began to implement policies in support of the ethanol industry,and from then till now,continues to do so
so,now biofuel industry is flourishing greatly in brazil.At last it can only be said that the biofuel industry has yet to see its great emergence and success.