Biofuels are derived from biomass of plants or of animal origin. Biofuels may be solid, gaseous or liquid, that are derived from the biomass. It comprises mainly wood, agricultural crops and products, aquatic plants, forest products, wastes and residues and animal wastes. Wood, agriculture wastes, charcoal, biomass briquettes used in rural areas for cooking, sugarcane bagasse used for electricity generation and steam in sugar industries are commonly known solid biofuels. Methane gas produced from anaerobic digestion of biomass, animal waste, waste water treatment sludge, household waste etc. by methanogenic bacteria and producer gas produced by pyrolysis of wood biomass, agricultural wastes are examples for gaseous biofuels. Liquid biofuels include bioethanol, biodiesel and other liquid fuels derived from the biomass. Bioethanol is produced from molasses, sugar cane, sugar beet, starchy crops such as potato, sweet potato, corn, etc. Ethanol is also produced from agricultural residues and other cellulosic biomass. Biodiesel is produced from the plant based oils and animal fats.
Scope for biofuels in India
India is sixth in the world in energy demand accounting for 3.5 % of world commercial energy consumption with about 85 % of its local requirement through imports. The country’s energy demand is expected to grow at an annual rate of 4.8 % over the next couple of decades. Most of the energy requirements are currently satisfied by fossil fuels. Domestic production of crude oil can only fulfill 25-30 % of national consumption. Thus, biofuels are going to play an extremely important role in meeting India’s energy needs.
Fortunately, India harbors over four lakh species of plants and over a hundred different species of higher plants are marked as potential oil trees across the country. The Karnataka state has recorded forest area of 43,356.45 sq. km (www.karnatakaforest.gov.in) and contains about 85 different species of plants, which have been identified for use as biofuel candidates. This includes some of the traditionally known species such as pongamia, neem, jatropha, mahua, simarouba, calophyllum, rubber tree etc. The seeds of these species possess more than 20 % oil that is well suited for biodiesel production. However, these potential oil producing plants are further needed to be studied systematically for oil content, seed oil extraction technique, oil composition, conversion of oil into biodiesel, suitability of biodiesel to use as an automobile fuel. Additionally, resources for biodiesel production in India can be greatly enhanced, since the country has approximately 100 million hectares of degraded land, which can be utilized for cultivation of biofuel crops without competing with the food crops.