What are Liquid Biofuels? – Types, and Application

As we all know, biofuels are renewable, alternative clean fuels derived from plants, industrial wastes, agriculture, and domestic wastes. It is a non-fossil fuel produced from biomass. We have already seen biofuels, their types, and their advantages.

Now let us discuss what liquid biofuels are, their types, advantages, and facts to know about liquid biofuels.

What are liquid biofuels?

Liquid biofuels offer an alternative fuel for all types of internal combustion engines running on gasoline, diesel, kerosene, including for use in passenger vehicles, trucks, ships, airplanes.

Biofuels are converted into essentials in three ways; They are chemical processes that use chemical agents for breakdown, thermal processes that use heat energy for the breakdown of raw materials, and biochemical processes that use bacteria to break down raw materials.

Biofuels can be broadly categorized into solid biofuels and liquid biofuels. Solid biofuels have been used for ages for the purposes of heating and lighting. Some examples of solid biofuels include wood, sawdust, charcoal, agricultural waste, dry manure, and firewood.

liquid biofuels

Solid biofuels are also known as primary biofuels. On the other hand, liquid biofuels are widely used in industries and automobiles. Some of the commonly used liquid biofuels are biodiesel, bioethanol, biogas, biobutanol, and biohydrogen. The energy emitted from biofuels is known as bioenergy.

Types of liquid biofuels


Bioethanol is one of the common promising liquid biofuels. It is a renewable source of energy that can easily be produced by the fermentation of sugar from crops. In the fermentation process, the necessary sugar energy comes from crops.

Commonly grown crops are corn, wheat crops, sorbet, corn, willow, reed canary grass, and umbilical grass. The production process of bioethanol is as follows;

  • The first step is milling. Here using a mechanical crusher, the grains of grain is crushed so that they release the starch components.
  • Now in the second stage, water and enzyme are added and heated so that the crushed components will be converted into fermentable sugars.
  • Now again the mashed ingredient is fermented using yeast and the sugar obtained is further converted to bioethanol and carbon dioxide.
  • The next step is distillation, concentrating, and cleaning of the bioethanol produced.
  • The final step of this process is drying and dehydration of bioethanol.

Bioethanol can also be produced from wheat grains. The process is an underdog;

  • Wheat is cleaned thoroughly. It is now put into a grinding mill that separates the bran from the grain.
  • In the second stage, gluten is squeezed out of the grain.
  • Enzymes are added to the mixture so that wheat is converted into fermented carbohydrates. It can again be fermented into alcohol.
  • During the fermentation process, carbon dioxide and alcohol are produced. The alcohol mixture is commonly called a mash.
  • Through the process of distillation, the alcohol is separated from the mash.
  • Now comes the improvement process. Here the wine is cleaned again.
  • The final stage is dehydration or alcohol drying. This process completely removes the amount of water in the alcohol. The end result is extremely high quality and purity bioethanol.


  • 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.


Biodiesel is another liquid biodiesel that is undoubtedly renewable. This is easily produced from waste animal fat and vegetable oil. It is biodegradable and causes very little pollution during burning. And it can be blended with petroleum diesel for vehicles. Cooking oil, animal fat and agricultural byproducts are the major components used in making biodiesel.

These elements undergo a chemical process, in which glycerin is extracted. The process of removing glycerin is called transesterification. The end products of this reaction are methyl esters commonly known as biodiesel and glycerin which are widely used in soap making.

This biodiesel is being used in diesel engines with very few modifications. A major attraction of using biodiesel is that it helps release dirt from engines that would otherwise accumulate fuel pipes and walls. This in turn reduces the vehicle’s efficiency and even stops the filter. The amount of energy in biodiesel is about 90% of petroleum.


  • 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.


Biobutanol is the secondary-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.

Advantages of Using Liquid Biofuels

  1. Renewable energy:

Liquid biofuels are a renewable source of energy compared to any other source. The main reason behind this is the fact that the raw materials used are plant waste, agricultural waste, household waste, and commercial waste. All these are available in abundance and thus become easily renewable.

2. No pollution:

When these liquid biofuels are ignited, a minimum amount of carbon dioxide is emitted. All these are covered under green and eco-friendly fuels. This in turn decreases pollution to a great extent.

3. Engine performance is high:

Liquid biofuels are utilized as an option in automobiles. Since it is a clean and pure fuel, the performance of vehicles is better and lasts longer.

4. Healthier environment:

By using these biofuels, pollution and carbon emissions are reduced which in turn adds to the quality of the air we breathe. It enhances a healthy life span along with the general health of humans.

5. Protection of ozone layer:

As mentioned above, the emission of greenhouse gases by these liquid biofuels is relatively low compared to fossil fuels. It is toxin-free. This protects the ozone layer from corrosion in a great way. All other environmental issues such as climate change will be under control.

6. Energy-efficient:

According to studies, these liquid biofuels have been shown to be more energy-efficient than diesel and petrol.

7. Control over prices:

Liquid biofuels are a better option and economical. Petrol and diesel prices are increasing on a daily basis. Better and advanced techniques should be developed to improve the quality and use of liquid biofuels. This, in turn, regulates the price of petrol and diesel. Thus, it will have a positive impact on the economy as a whole.

Facts to know about liquid biofuels:

  • Biodiesel has the highest energy balance.
  • Biofuels can be applied in cars and other vehicles
  • Biodiesel is usually added to petrol and diesel to reduce carbon emissions.
  • The United States is the world’s largest generator of bioethanol.
  • According to the study, more than 1 billion gallons of biodiesel and 22 billion gallons of bioethanol are produced every year.
  • Biofuels can be in solid, liquid, and even gaseous forms.


Liquid biofuels can be appreciated as an asset to the economy. Keeping in view its availability, more intensive studies, and research should be done so that it can be used wisely. Awareness programs should be conducted so that more people know the benefits of using liquid biofuels.

It can also be used as an alternative to diesel and petrol which will reduce the monopoly of fuel. As such, it is an upside for the renewable resource economy overall.

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