Biofuel is a generic term that refers to fuel derived from biomass, such as plants and organic wastes. The International Energy Agency (IEA) adopts a simplified classification of biofuels based on the maturity of the technology deployed. This taxonomy uses terms like “conventional” and “advanced” to distinguish between different types of biofuels.
Conventional biofuels, i.e., the first generation biofuels, include sugarand starch-based ethanol, oil-crop based biodiesel and straight vegetable oil, as well as biogas derived through anaerobic digestion. The technology for conventional biofuel is well-established and is being deployed for producing biofuels on a commercial scale. The most common conventional biofuels that are largely used as transport fuels are ethanol and biodiesel. Both ethanol and biodiesel are used in internal combustion engines either in its pure form or more often as an additive.
The second generation biofuels are already an improvement in producing biofuels from feedstock of lignocellulosic, non-food materials that include straw, bagasse, forest residues and purpose grown energy crops on marginal lands. Projects are needed to maximise the amount of renewable carbon and hydrogen that can be converted to fuels from “second generation” biomass.
The third generation biofuels are based on algal biomass production. They are presently under extensive research in order to improve both the metabolic production of fuels and the separation processes in bio-oil production to remove non-fuel components and to further lower the production costs.
The fourth generation biofuels—photobiological solar fuels and electrofuels—are expected to bring fundamental breakthroughs in the field of biofuels. Technology for production of such solar biofuels is an emerging field and based on direct conversion of solar energy into fuel using raw materials that are inexhaustible, cheap and widely available. This is expected to occur via revolutionary development of synthetic biology as an enabling technology for such a change.
India’s biofuel production accounted for only 1 percent of global production in 2012. Bio-ethanol and bio-diesel are the two biofuels that are commercially produced. Biofuel industry is yet to fully mature in India and it is difficult for the industry to sustain without subsidies, fuel mandates, or other government support. As biofuels are usually regarded as cleaner and greener alternatives to fossil fuels, the design of the subsidies and other policy supports to the sector is also generally done by keeping the potential positive benefits in view.
In India, ethanol is predominantly produced from sugarcane molasses—a by-product of sugar production. Ethanol production in India, therefore, depends largely on the availability of sugar molasses, which in turn depends on the production of sugarcane. Since sugarcane production in India is cyclical, ethanol production also keeps fluctuating from one year to another, often failing to meet the optimum supply level required to meet the demand at any given point in time. Lower availability of sugarcane molasses and consequent higher molasses prices also affect the cost of production of ethanol. The new Indian government has been mulling over a 10 per cent ethanol blending that is expected to reduce import of petroleum by $3 billion a year.
The lack of availability of jatropha seeds production, most of the biodiesel units are not operational most of the year. There are about 20 large-capacity biodiesel plants in India that produce biodiesel from alternative feedstocks such as edible oil waste (unusable oil fractions), animal fat, and inedible oils. Presently, the total commercial production and marketing of jatropha-based biodiesel in India is small, with estimates varying from 140 to 300 million litres per year.
The Indian biofuel policy
The Indian economy is growing at the rate of approximately 7% since 2000.
The biofuel policy of India has an indicative target of 20 percent blending of bioethanol by 2017 . India has 330 distilleries, which can produce more than 4 billion litres of rectified spirit (alcohol) per year in addition to 1.5 billion litres of fuel ethanol which could and should meet the requirement of 5% blending.
Microalgae is in focus as a future source of biodiesel due to the advantages of yielding 30 times more oil compared to other oil seed crops. Microalgae, the small microorganisms, can grow in fresh, marine, waste and saline water. Microalgae have the potential to produce 1,36,900 liters while Jatropha can produce 1,892 liters oil per acre Microalgae can fix large amount of carbon dioxide (CO2) and contribute about 40-50% oxygen in the atmosphere, thereby, supporting biological life on our planet by producing food, medicines, chemicals etc for human consumption. Microalgae, with rich biodiversity with over 50,000 species, exist all over the world, but only 30,000 are analyzed so far. It is also known that many species of microalgae have the ability to accumulate lipids as triacylglycerols (TAGs).
Microalgae are becoming important as source of biofuel due to the following advantages:
• Can grow rapidly with solar energy conversion efficiency higher than other terrestrial plants due to their simple structure.
• Oil yield is approximately 30 times more than the terrestrial oil seed plants.
• Can grow on non-arable land.
• Can grow in waste, marine and saline water.
• Can use waste CO2 sources, thereby, potentially mitigating the release of GHGs into the atmosphere.
• Cultivation consumes less water than land crops.
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