Renewable Energy

 The form of energy obtained from natural resources like wind, sunlight, water and heat are termed Renewable energy. The most common example includes electricity generated from solar energy, wind power, hydropower, biomass, geothermal resources, and biofuels. Among the different source of renewable energy, biofuel or green energy is gaining much significance. Biofuels are the form of energy derived from living organisms or a biomass or as a metabolic by-product. In some cases these can also be considered as fossil fuel. But apart from conventional fossil fuel, biofuel never results in raise in CO2 level in atmosphere.

The term in general can be used for any solid biomass, liquid fuel and biogases. Biofuel can be widely classified as first second and third generation biofuels. Fuels obtained through conventional technology using sugar, animal fat, vegetable oil or starch as feed stock are termed ‘First generation biofuels’. For example, the bioethanol obtained by fermentation of starch and biodiesel from seeds or grains of plants like jatropha, sunflower etc. Whereas, ‘Second generation biofuel’ are obtained by fermentation of cellulosic component of plant which is separated from lignin using second generation technology. Major goal behind development of second generation biofuel technology is to overcome limitations faced by first generation biofuels and to increase the amount of biofuel produces continuously using biomass like non food part of crops and non food crops.

The most commonly used feedstock for production of second generation biofuel is lignocellulosic crops like willow, poplar miscanthus and wheat straw. Third generation Biofuel or Algae biofuel uses algae as a major source of energy. Major studies are focused around species like Chlorella vulgaris, Botryococcus braunii, Sargassum etc. Many companies around the world are conducting research to develop bio-chemical and thermo-chemical processes for the production of green fuels like green gasoline, green diesel, and green aviation fuel.

Although there is no specific definition for fourth-generation biofuels, it can be referred as biofuels obtained processes like pyrolysis, upgrading, gasification or genetic manipulation of organisms, other than first second or third generation biofuels technologies.

Some of the most common biofuels are

•    Bioalcohol- alcohol fuels like ethanol and methanol, obtained from biological source are called bioalcohol. There is no chemical difference between alcohol fuel produced from biological source and other sources.

•    Green diesel- biofuel derived from renewable feedstock like oils, algae, jatropha etc through fractional distillation are termed Green diesel.

•    Biodiesel- biodiesel is different from green diesel in that it is produced from vegetable oil, animal fat, jatropha, seeds, palm oils etc using transesterification and is chemically similar to conventional fossil diesel.