Bio-Fuel Technology: Powering the Future of Aviation

Bio-fuels have now become a global necessity due to the international commitment to reduce Green House Gases (GHGs) and emissions in consonance with the Kyoto Protocol

Issue: 02-2019By Isha Jaiswal & Zorawar Singh JaiswalPhoto(s): By United AirlinesIllustration(s): By Vimlesh Yadav

The last century saw a preponderance in the consumption of crude oil derivatives and the development of technologies at a very fast pace. Consequently, all machines including aircraft today are heavily dependent on crude oil products. Crude oil is a diminishing resource. As the consumption of oil escalates, its polluting emissions too will rise along with its price. As a result, a time will come when the supply and demand ratio is going to make petroleum products prohibitively expensive, thus, forcing us to find and adopt alternative, sustainable fuels which have lower emissions, are cheaper and biodegradable; but are especially synthesised for aircraft as per aviation norms of density, freezing points, specific impulse and their ability to be used in the existing fleet of aircraft.


Scientists the world over are exploring the feasibility of finding a replacement for Aviation Turbine Fuel (ATF). So far, scientific research has permitted up to a 50 per cent blend of bio-fuels with ATF without any loss of efficiency. The major bio-fuels produced include bio-diesel and bio-ethanol blended ATF. Bio-fuels can be defined as flammable liquids that are produced from organic substances or biomass, for example, from plants and organic waste. Usually, only that kind of bio waste is used which is not consumed by humans or domestic animals to avoid demand-based competition. The significant aspect of bio-fuels is that these are easily replenishable viz a viz conventional fuels. There is no sulphur in them and the emission levels too are lower. Sugar and starch is used to produce ethanol that can be blended safely with ATF. India produces significant amount of sugar that has molasses as a byproduct in the sugarcane industry. Molasses too is used to produce ethanol. Bio-fuels are also produced from oil-based crops and biogas is the product of anaerobic digestion of organic substrate.


Ethanol is of first generation and the most commonly used bio-fuel that is produced using sugarcane and molasses. Alternatively, oil-based crops that are inedible by humans and domestic animals too are decomposed to produce bio-gas which in turn produces bio-fuels by bacterial decomposition. The second-generation bio-fuels are derived from the feedstock of animals, forest refuse and non-revenue generating plants which grow on the fringes of human settlement and agricultural areas. These products too are decomposed to produce bio-fuels by the Pyrolysis process which heats the organic substrate to very high temperatures in an inert atmosphere. The exude is then used to produce bio-fuels. In this scenario, the issue of competition for land and water for irrigation to produce such bio-fuels will always be a conflicting requirement. The greater the amount of land and water needed for producing such bio-fuels; the greater will be the conflict for resources required by humans for food viz a viz those needed for the production of bio-fuels for aviation. Hence, it is best to use the fringe areas along plantations or farmlands which are usually not used by the farmers to produce such a substrate.

In addition, the organic matter naturally occurring in the jungles and being wasted away by nature through natural decomposition or posing as a forest fire hazard, can also be harnessed within the forest area itself to produce such bio-fuels. This methodology produces aviation bio-fuels without conflicting with human energy and food requirements. As it is, laws relating to forests are so strict in India that human settlements cannot encroach onto forest land. Consequently, an assured acreage of forest area is available to aviation bio-fuel producers. The third generation is a promising method of obtaining biofuels from the use of algae biomass. It requires no land, but some water. In fact, both fresh and saline water bodies can be used to produce bio-fuels from the algal growth. Growing algae requires the least amount of human effort. However, the technology to economically extract bio-fuels is still in a nascent stage. Once the commercial grade technology is developed, it will become the most economical of all bio-fuel producing models. No land, merely some natural water, no additive substrate, but just a harnessing technology is needed for collecting the bio-fuels and its logistics.


Photo-biological solar fuels constitute the fourth generation of bio-fuel’s production process. It uses solar photo electric cells and organic matter to produce bio-fuels. It is suitable for places with abundant sunshine, but scarce water such as deserts. However, research is still being done in this aspect to come up with commercially viable technologies and processes. Jatropha seeds produce bio-diesel. However, the quantity of jatropha seeds produced is quite low. Thus, the quantum of bio-diesel produced too is meagre. It takes about three years for jatropha seeds to produce a viable quantum of diesel. Hence, currently, the product life cycle due to the gestation period needed for the maturity jatropha seeds, does not seem promising. Today, bio-technology and agriculture scientists are working to shorten the gestation period of jatropha products.

Bio-fuels have now become a global necessity due to the international commitment to reduce Green House Gases (GHGs) and emissions

The bio-fuel produced by first generation derivatives have already entered the commercialisation phase. This is the least technology-intensive process for bio-fuel production. The second generation process is also maturing as a concept. This however needs legislative changes in India as the extraction of bio-fuels means commercial activity within the forest. India now has to use this process to produce bio-fuels and reduce its deficit. The third generation bio-fuel production process using algae and saline or waste water, is the next most suitable option when this technology matures. There is a need to invest in these technological concepts now to reap dividends in the foreseeable future. The fourth generation process will also be able to produce sufficient bio-fuels due to the tropical location of India which allows for abundant sunshine. This will be possible in the years to come as the solar technology has yet not matured and is expensive. Financially, as of now, the first generation technology is the most cost-effective today. The price of bio-fuels increases as the generation number increases. However, as technology improves with time, this relationship will reverse itself.


India is lucky to be located in the tropics to enable production of bio-fuels. The first generation bio-fuels which depend on agro products for raw materials can be best grown in the states such as Punjab, Haryana, Uttar Pradesh, Maharashtra, Tamil Nadu, and Kerala. The reason is that these states are the bread baskets of India. They produce considerable quantity of agricultural waste from sugarcane, wheat, paddy, vegetables and other crops.

Second generation bio-fuels are dependent on forest waste or organic substrate. Hence, the states in the North Eastern Region, Kerala, the riverine delta of West Bengal, Madhya Pradesh, Kerala, Tamil Nadu and to a limited extent, reserved forests such as Gir in Gujarat are best poised to produce quantities of bio-fuels from forests that are financially viable. Third generation bio-fuels can be economically produced along the complete Indian coastline, Bihar, Assam, Meghalaya, Orissa, West Bengal and in the foothills of the Himalayas. These places have abundant fresh and city-based waste water too that can be used to produce bio-fuels.


Fourth generation bio-fuels are best produced in Rajasthan and the salt plains of Gujarat. These areas have abundant sunshine and vast expanses of land which are required to deploy solar cellbased bio-fuel production infrastructure. These states have sparse population and comparatively less cultivation. Hence, they would be the most suitable for harnessing sunlight to produce bio-fuels.

India has got a large number of chemists and engineers. Entrepreneurs can set up Research and Development facilities in these areas and employ trained personnel to devise bio-fuel production processes. This nascent field, if captured by India, can enable the nation to become a net exporter of bio-fuels blended aviation fuels which is the future.


Bio-fuels have now become a global necessity due to the international commitment to reduce Green House Gases (GHGs) and emissions in consonance with the Kyoto Protocol. The International Civil Aviation Organisation has behaved very responsibly and has, on its own, articulated a target to reduce aviation emissions to the levels of the year 2005 by the time we reach the year 2022. Moreover, it has also planned to achieve lower level emissions by the year 2050. This can only be possible by introducing greener engines and by ushering in financially competitive bio-fuels which will constitute the future of aviation.