Biofuel: Definition, Types, Generation, Pros & Cons

What is a Biofuel?

Biofuel, any fuel that is derived from biomass that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas.

In contrast to other renewable energy sources, biomass can be converted directly into liquid fuels, called “biofuels”, in order to meet the demand for transport fuels. The two most common types of biofuels used today are ethanol and biodiesel, both of which represent the first generation of biofuel technology.

Biofuels are biomass-based transportation fuels such as ethanol and diesel fuel made from biomass materials. These fuels are usually mixed with petroleum fuels (gasoline and distillate/diesel fuel and heating oil) but can also be used on their own.

Using ethanol or biodiesel reduces the consumption of gasoline and diesel fuel from crude oil, which can reduce the amount of crude oil imported from other countries. Ethanol and biodiesel are also cleaner fuels than straight gasoline and diesel fuel.

Generations of Biofuels

There are three types of biofuels: 1st, 2nd, and 3rd generation biofuels. They are characterized by their sources of biomass, their limitations as renewable sources of energy, and their technological progress.

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  • First-generation biofuels: First-generation biofuels are produced from sugar, vegetable oil, starch, or animal fat using standard technology. Common first-generation biofuels include biodiesel, bio ether, vegetable oil, bio alcohol, biogas.
  • Second-generation biofuels: These originate from non-food crops, such as cellulosic biofuels, and waste biomass such as wheat and corn stalks and wood, etc. Examples include advanced biofuels such as biofuels, bio methanol.
  • Third Generation Biofuels: These are produced from microbes like algae. Algae consist of 40% of lipids that can be converted into biodiesel or synthetic petroleum. Algae has the potential to produce the most energy among all sources.
Biofuel is defined as fuel that is produced through contemporary processes from biomass, rather than by the very slow geological processes involved in the formation of fossil fuels, such as oil.

Types of Biofuels

The two most common types of biofuels in use today are ethanol and biodiesel, both of which represent the first generation of biofuel technology.

1. Biodiesel

Biodiesel is a liquid fuel made from renewable sources such as new and used vegetable oils and animal fats. It is a clean substitute for petroleum-based diesel fuel. Biodiesel is non-toxic and biodegradable and is made by combining alcohol with vegetable oil, animal fat, or recycled cooking fat.

Like diesel fuel made from petroleum, biodiesel is used to fuel compression-ignition (diesel) engines. Biodiesel can be mixed with petroleum diesel in any percentage, including B100 (pure biodiesel) and B20 (a blend containing 20% biodiesel and 80% petroleum diesel).


  • It is also renewable! Sufficient plant, algae, or bacterial crops can provide abundant biodiesel fuel.
  • It is recycled! A lot of biodiesel on the market is derived from used cooking vegetable oils.
  • Domestic production reduces dependence on foreign fossil fuels and promotes rural agricultural economies.
  • Tailpipe reduces emissions, burns cleaner, and does not contain sulfur, eliminating sulfur dioxide emissions, compared to petroleum-based diesel.


  • Biodiesel is currently more costly to create commercially than petroleum diesel because the production foundation is not yet large scale
  • Biodiesel is sensitive to a cold climate and can gel when the temperature falls, causing fuel injection difficulties (although this can be set with expensive engine modifications).
  • While many diesel vehicle engines can run on biodiesel with minimal or no modification, biodiesel does not work in standard gasoline engines.
  • Biodiesel production increases food costs, both are used to generate biodiesel in food crops, as well as feedstocks for biodiesel to produce algae and bacteria.

2. Ethanol

Ethanol (CH3CH2OH) is a renewable fuel that can be made from various plant materials collectively referred to as “biomass”. Ethanol is an alcohol that is used as a blending agent with gasoline to increase octane number and reduce carbon monoxide and other smog-causing emissions.

The most common ethanol blend is E10 (10% ethanol, 90% gasoline). Some vehicles, known as flexible-fuel vehicles, are designed to run on E85 (a gasoline-ethanol blend containing 51 to 83% ethanol, depending on geography and time of year), alternative fuel with a much higher ethanol content than regular Petrol. About 97% of the gasoline in the United States contains some ethanol.

Most of the ethanol is made from plant starch and sugar, but scientists continue to develop technologies that allow the use of cellulose and hemicellulose, the inedible fiber material that makes up most of the plant material. In fact, several cellulosic ethanol biorefineries are currently operating on a commercial scale in the US.

The common method of converting biomass to ethanol is called fermentation. During fermentation, microorganisms (e.g. bacteria and yeast) metabolize plant sugar and produce ethanol.


  • It is renewable! Ethanol can be regenerated by giving sufficient crop yields.
  • Domestic production reduces dependence on foreign fossil fuels and promotes rural agricultural economies.
  • Ethanol burns cleaner than gasoline, releasing about 15 percent less greenhouse gas emissions
  • Improvements in cellulosic ethanol can make ethanol fuel from scrap cellulose such as scrap wood, food by-products, and non-food plants such as switchgrass


  • Ethanol received from corn, beets, and sugarcane plays directly with the food supply, raising the cost of other foods and grain-fed meats.
  • Cultivated ethanol crops destroy the soil and use toxic industrial agricultural chemicals that can contaminate the water supply.
  • Ethanol has less energy than gasoline, reducing fuel mileage by between 15 and 30 percent
  • It currently requires more energy to make large amounts of ethanol; However, cellulosic ethanol may be the “magic bullet” to solve it and the food competition dilemma.
  • High blends or pure ethanol may be corrosive on which it is not designed to run, and cannot be carried through existing oil pipelines due to corrosion restrictions.
  • Transforming a standard gasoline engine to operate on large mixtures or purified ethanol can be costly from several hundred to thousands of dollars.

3. Biobutanol

Biobutanol is four-carbon alcohol produced by the fermentation of biomass. It has a long hydrocarbon chain which renders it non-polar. The production of biobutanol can be carried out in ethanol production facilities. The primary use of biobutanol is as a fuel in internal combustion engines.

Biobutanol is the second known fuel between the three biofuels, but it has the largest potential. Biobutanol is iso-butanol made from algae or bacteria instead of animal or vegetable fats such as biodiesel. Standard petrol engines can use Biobutanol without prior engine modification. Biobutanol is mostly obtained from fermenting sugar from the organic feedstock.

The most commonly used method of producing biobutanol ferments simple sugars found in biomass feedstock. A by-product of this fermentation process is butanol, in addition to acetone and ethanol. Biobutanol can reduce carbon emissions by a significant 85% compared to gasoline, making it a more viable alternative to gas and fuels that are a mixture of gasoline and ethanol.

At very high concentrations, biobutanol is mixed with conventional gasoline instead of ethanol for use in non-petrol engine models. Research has proved that biobutanol at 100 percent is usable in unmodified engines.


  • It is also renewable! Biobutanol is formed from algae or bacteria.
  • It can be used directly in a gasoline engine without modification.
  • It can utilize the existing pipeline and supply chain foundation for delivery.
  • It has a high-octane level, so if there is any loss in fuel mileage, it is very low.
  • Non-corrosive for engines and pipelines
  • Domestic production decreases dependency on imported fossil fuels


  • Feedstocks are required for production, although non-edible feedstocks and genetically modified bacteria and algae strains may resolve the issue.
  • Production costs are relatively high, but the industry is still in its infancy, and costs will decrease as it increases.

4. Biogas

Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen (anaerobically), primarily consisting of methane and carbon dioxide. It can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste.

Biogas is a renewable source of energy produced by the anaerobic digestion of biomass. In simple words, biogas is obtained when organic matter breaks down in the absence of oxygen. The raw elements used are compost, food waste, local waste, farming waste, and sewerage.

The main ratio of biogas is methane and carbon dioxide. It also has little symmetries of hydrogen sulfide, hydrogen, carbon monoxide, and siloxanes. Biogas is commonly used for heating, electricity, and automobiles.

5. Biohydrogen

Petroleum fuels such as gasoline, diesel, and jet fuel contain a complex mixture of hydrocarbons (hydrogen and carbon molecules) that are burned to produce energy. Hydrocarbons can also be produced from biomass sources through a variety of biological and thermochemical processes. Biomass-based renewable hydrocarbon fuels are nearly identical to the petroleum-based fuels they are designed to replace, making them compatible with today’s engines, pumps, and other infrastructures.

Currently, a commercial-scale facility (World Energy in Paramount, California) is producing renewable diesel from waste fats, oils, and fats. Several companies are interested in either retrofitting existing industrial sites or building greenfield plants for renewable diesel and jet engines in the USA.

What are the advantages and disadvantages of biofuels?

Advantages of Biofuels

1. Efficient Fuel.

Biofuel is made from renewable raw materials and is relatively less-flammable compared to fossil diesel. It has significantly better lubricating properties. It causes fewer harmful carbon emissions than standard diesel. Biofuels can be made from a variety of materials. The total cost-benefit ratio is much higher.

2. Cost-Benefit

Biofuels will now cost the same on the market as gasoline. However, the total cost-benefit ratio is much higher. They are cleaner fuels, which means they produce fewer emissions when burned. With the increased demand for biofuels, they have the potential to become cheaper in the future too.

3. Durability of Vehicles’ Engine

Biofuels are adaptable to current engine designs and work very well in most conditions. It has higher cetane and better lubricating properties. When biodiesel is used as a combustible fuel, the life of the engine is increased.

4. Easy Source

Gasoline is refined from crude oil, which happens to be a non-renewable resource. Although current gas storage facilities will last for many years, they will end at some point in the near future. Biofuels are made from many different sources, such as liquid manure, crop waste, other by-products, algae, and plants that are specially grown for fuel.

5. Renewable

Most fossil fuels expire and one day they end in smoke. Since most sources such as manure, corn, switchgrass, soybeans, crop, and plant waste are renewable and unlikely to run out anytime soon, using biofuels in nature is efficient. These plants can also be replanted again and again.

6. Reduce Greenhouse Gases

Studies suggest that biofuels reduce greenhouse gases by up to 65 percent. When burned, fossil fuels produce large amounts of greenhouse gases; i.e., Carbon dioxide in the atmosphere. These greenhouse gases trap sunlight and cause the planet to warm up.

7. Economic Security

Not every country has large reserves of crude oil. For them, the import of the oil is an enormous burden on the economy. As more people switch to biofuels, a country can reduce its dependence on fossil fuels. The production of biofuels increases the demand for suitable biofuel crops and gives agriculture a boost.

8. Reduce Dependence on Foreign Oil

While locally grown crops have reduced the country’s reliance on fossil fuels, many experts believe it will take a long time to meet our energy needs. With crude oil prices skyrocketing, we need more alternative energy solutions to reduce our dependence on fossil fuels.

9. Lower Levels of Pollution

Because biofuels can be made from renewable resources, they cause less pollution on the planet. However, this is not the only reason biofuels are being promoted. When burned, they release less carbon dioxide and other emissions than standard diesel. Its use also leads to a significant reduction in PM emissions.

Disadvantages of Biofuels

1. High Cost of Production

Despite all of the advantages associated with biofuels, they are quite expensive to produce in the current marketplace.

2. Monoculture

Monoculture refers to the practice of producing the same crops year after year, rather than producing various crops through a farmer’s fields over time.

3. Use of Fertilizers

Biofuels are made from crops, and those crops need fertilizers to grow better. The disadvantage of using fertilizers is that they can have harmful effects on the environment and cause water and Agriculture pollution.

4. Shortage of Food

Biofuels are made from plants and plants with a high sugar content. However, most of these plants are also used as food crops. Even if vegetable waste material can be used as raw material, the need for such food crops remains. It will take up agricultural land from other crops, which can cause a number of problems.

5. Industrial Pollution

The carbon footprint of biofuels when burned is smaller than that of conventional fuels. However, the process by which they are made makes up for it. Production is largely dependent on a lot of water and oil. It is known that large industries that are supposed to produce biofuels emit large amounts of emissions and also cause small amounts of water pollution.

6. Water Use

Irrigation of biofuel crops requires large amounts of water which, if not managed carefully, can put a strain on local and regional water resources. To produce corn-based ethanol to meet local demand for biofuels, huge amounts of water are used that could not put sustained pressure on local water resources.

7. Future Rise in Price

Current biofuel production technology is not as efficient as it should be. Scientists are busy developing better ways that we can get this fuel. However, the cost of research and future installation means that the price of biofuels will increase significantly.

8. Changes in Land Use

If the land is used to grow a biofuel feedstock, it has to be cleared of native vegetation, which then leads to ecological damage

9. Global Warming

The biofuels, which are mainly hydrogen and carbon, produce carbon dioxide, which contributes to global warming. While biofuels cause fewer greenhouse gas emissions than fossil fuels, this can only serve to slow global warming, not stop it or reverse it.

10. Weather Problem

Biofuel is less suitable for use at low temperatures. It is more likely to attract moisture than fossil diesel, which causes problems in cold weather. It also increases the microbial growth in the engine which clogs the engine filters.


What is a Biofuels?

Biofuel, any fuel that is derived from biomass that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas.

How are biofuels made?

Biodiesel is a liquid fuel produced from renewable sources, such as new and used vegetable oils and animal fats, and is a cleaner-burning replacement for petroleum-based diesel fuel. Biodiesel is non-toxic and biodegradable and is produced by combining alcohol with vegetable oil, animal fat, or recycled cooking grease.

What is the definition of biofuels?

Biofuel is defined as a fuel that is produced through contemporary processes from biomass, rather than by the very slow geological processes involved in the formation of fossil fuels, such as oil.

What are the types of Biofuels?

Types of Biofuel:
1. Biodiesel
2. Ethanol
3. Butanol.
4. Biogas.
5. Methanol.
6. Biohydrogen

What are the generations of biofuels?

Generations of biofuels:
First-generation biofuels – First-generation biofuels are made from sugar, starch, vegetable oil, or animal fats using conventional technology.
Second-generation biofuels – These are produced from non-food crops, such as cellulosic biofuels and waste biomass (stalks of wheat and corn, and wood).

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