Biofuels are biomass-derived liquid fuels, which is a perfect substitute for liquid fossil fuels. Since biomasses are continually being replenished naturally, biofuels considered renewable sources of energy. Biofuels are mostly used as a transport fuel. The transport sector accounts for about one-fourth of total energy consumed globally and it heavily depended on crude oil and oil products. But the growing energy demand, fast depleting fossil fuels, and its adverse effect on climate changes increase the importance of clean and renewable fuels like biofuels. Biodiesel and Bioethanol are the most common types of biofuels produced globally from several resources of biomass, such as food crops, crop wastes, woody parts of plants, municipality waste, and algae.

• Bioethanol is an alcohol fuelmade from any raw material containing significant amounts of sugar (e.g., sugar cane or sugar beet) or starch (e.g., maize or wheat) and by the process of fermentation. Ethanol can be used as fuel in its pure form (E100), but it commonly blended with gasoline to increase octane and improve vehicle emissions. Brazil and the United States are the biggest exporters and consumers of ethanol.

• Biodiesel is produced by the process of transesterification of vegetable oil or animal fat or recycled cooking grease. Most often it is blended with petroleum diesel in ratios of 2%(B2), 5% (B5), and 20% (B20) or as pure biodiesel (B100).

Global production of biofuels has been growing steadily over the last decade. About 160 billion litres of biofuels were produced globally in the year of 2018 with a growing annual rate of 13% from year 2000. Bioethanol share the largest with 62% growth followed by FAME biodiesel with 26%. But this green transition has many critical challenges. Global biofuel output still needs to triple by 2030 in order to meet the International Energy Agency's targets to track with sustainable development scenario. Countries globally accelerated their biofuel production capacity to meet this target.

Type of BIOFUELS

Biofuels categorized into four generations depending on the nature of biomass and production technology used.

First-generation biofuels are produced from edible food items such as starch, sugar, and any type of vegetable oil and animal fats through traditional fermentation or chemical process. However, the future success of first-generation biofuels is limited as it has major impacts on greenhouse gas emissions, foodsecurity, biodiversity and land, and water usage. Bioalcohols, biodiesel, biogas are few common examples of first-generation biofuels.

Second-generation biofuels or cellulosic biofuels mainly based on non-edible food sources. Agricultural waste like wheat straw, corn husks to municipality wasteall are used as feedstockfor the production of second-generation biofuels. Advanced biofuels like biohydrogen, biomethanolare few examples of second-generation biofuels

Third-generation biofuels are also known as algal fuel since they are produced from the algae. All types of biofuels such as biodiesel, gasoline, butanol, andethanol can be produced from algae with a high yielding ratio.

Fourth-generation biofuels are the latest introduction of biofuel technology, where scientist targeting genetically modified feedstock for simultaneous production of bioenergy and capturing and storing of carbon dioxide (CO2).

Renewable biofuels are essential for a carbon-neutral bioeconomy. However, the competence of biomass production is toolow to be able to fully replace fossil fuels. Inorder to reduce this dependency on petroleum, constant research for additional next-generation fuels and new production methods is very much required.

Reference:

1. Global bioenergy statistics 2020: World Bioenergy Association.