The recent excitement over the Kyoto protocol pertaining to global climate change, the rising prices of fossil fuels has led India and other developing countries to look for an environmentally friendly and economically viable alternative fuels. Several initiatives have been taken in recent times on the energy front such as large scale promotion of wind energy farms, installation of solar panels for power generation, blending of ethyl alcohol with petrol and developmental efforts towards biofuels or green fuels.
- Vegetable oils (sunflower, soy, olive, etc.)
- Biodiesel: It is obtained from oil extracted from Curcas seeds. Production of biodiesel involves two step approach: extraction of the oil from seeds and the conversion of the extracted oil to biodiesel.
- Ethanol: obtained by distillation from energy crops like sugarcane, maize, switchgrass and residues.
- Methanol: Wood alcohol obtained by pyrolysis of energy crops or waste.
- Methane: gas obtained by bacteriological decomposition from landfill sites, sewage sludge, etc. Thus, this fuel solves two purposes, first of handling the solid waste efficiently, second of being environmentally safe.
A biofuel is a fuel that contains energy from geologically recent carbon fixation. These fuels are produced from living organisms. Examples of this carbon fixation occur in plants and microalgae.
A biomass conversion process makes these green fuels which then serves this planet as energy green warriors. Biomass refers to currently living organisms, most often referring to plants or plant-derived materials, rather than fossil fuels which are made millions of years later.
The biomass obtained from living organisms like plants and plant derivatives are then converted to convenient energy sources through three different processes which involves thermal (heat) conversion, chemical conversion and biochemical conversion. The fuel after these conversion processes are obtained in the three states: solid, liquid and gas and the biomass conversion can the serve the biomass for biofuels. Biofuels have increased in popularity because of rising oil prices and the need for energy security.
Carriage, storage and handling safety
Vegetable oils and biodiesel are biodegradable, non-toxic, non-carcinogenic, non mutagenic and non-allergic. This is of considerable ecological advantage when considering the pollution that has been caused by petro fuels following large scale marine oil spills-vegetable oils having been used to clean up oil slicks. Flashpoint is the lowest temperature at which the vapour of a flammable liquid ignites in air. Flashpoint is generally lower than the autoignition temperature. The flash point is higher degree Celsius for vegetable oils than diesel fuel, which means that the transport, storage and use is easier as the fire hazard is far below and any other currently available liquid transport fuel.
Methane is naturally occurring greenhouse gas, which is also the major component of CNG. It is non toxic and carries the same safety precautions as of any of the liquefied gases currently dispensed from pressurised containers.
Growing biofuels should be considered essentially non-polluting in the longer term, given proper agricultural and process management. In addition, by absorbing carbon dioxide from the atmosphere, energy crops act as carbon sink throughout the year! This is released only the fuel is used or the by-products are burnt. Longer term carbon sequestration is achieved through the roots and stubble of the plants being ploughed into the ground.
There is a wide range of plants available, worldwide, as oil-producing energy crops. Other major benefit of energy crops is the oxygen by-product from photosynthesis.
Ethanol, methanol, vegetable oil, and biodiesel are all oxygenated fuels. That is, they contain oxygen in their molecular structure. This is significantly advantageous to the burning process in an internal combustion engine, not only in improving the efficiency of the fuel but also in turning noxious oxides into less harmful dioxides (carbon and nitrogen). This also applies when used as fuel extenders.
In addition, none of them contains any sulphur at all unless minute traces are acquired through crop dusting, acid rain during growth or contaminated alcohols used during manufacture. Biodiesel is a better burning fuel than petro diesel and has a higher cetane number. This is due to the molecular oxygen content content of the fuel, which reacts under pressure and temperature faster than the subsequent fuel/ air mixture. This causes the fuel to burn at a higher temperature, resulting in the formation of a higher level of nitrogen oxides. By simply retarding the fuel injection timing by two to three degree (depending on the engine design), the burning temperature is reduced, thereby reducing the amount of nitrogen oxides gases formed.
Forest resources as Green fuels
Wood, which has chief advantages and various applications in the industrial and domestic processes, is the chief product of forests. Wood when used as fuel serves has certain advantages, over coal as its sulfur and ash contents are very low but at the same time excessive use of fuel woods increases pressure on forests and thus give way to deforestation. Wood may also be converted to solid and gaseous fuels.
Vegetable oil is the most energy positive fuel to produce requiring only agricultural input and seed pressing.
The importance of green fuels as alternate, energy sources as been well recognized in India.
However the generation and consumption of biofuels and these green fuels have been taken out of the picture due to certain drawbacks on the economic, social, environmental and technical backgrounds. This has been made popular through the paparazzi, scientific conferences and journals on the basis of certain debatable issues like: “Fuel Vs. Food”, “Biodiversity Vs. Biofuels”, etc.
Some others areas which need to be rechecked while generating green fuels are:
- Reduced energy efficiency and low energy quotient
- Poverty reduction potential.
- High carbon emissions levels.
- Sustainable biofuel production.
- Deforestation and soil erosion.
- Loss of biodiversity
- Impact on water resources is others.
Thus, the conclusion that we draw upon is that these green fuels are at first, cost effective as and when compared with oil prices. Secondly, these green fuels act as environment saviors and thus reduce the pressure on environmentally available sinks for greenhouse gases. Thirdly, these biofuels save to the extent of using fossil fuels and thus save the fossil fuels for our future generation since they take millions and billions of years to recover and compensate for the present uses. However, these biofuels increase pressure on forest resources and other plants and plant derivative materials.