Biodiesel: fuel of the future?
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Biodiesel resources can provide energy security
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WITH THE upsurge in economic activities, India is consuming over a whopping 127 million tonnes of crude oil a year and is forced to import about 70 per cent of its needs. The current yearly consumption of diesel alone is approximately 40 million tonnes in India constituting about 40 per cent of all petro-products.
In the current scenario, exploring energy alternatives in the form of bio-fuels, namely, ethanol and biodiesel assumes top priority.
Biodiesel, derived from the plants (bearing oils) like sunflower, rapeseed, canola or Jatropha Curcas, can be used as a substitute or an additive to diesel.
Biodiesel can provide power similar to conventional diesel and thus can be used in diesel engines. Biodiesel is non-toxic and environment friendly as it produces substantially less carbon monoxide and the combustion gasescontain no sulphur dioxide and unburnt hydrocarbons.
Cancer risk reduced
Because of these properties cancer risks and neonatal defects are reduced. Biodiesel mixed (5-20 per cent) with conventional diesel can extend engine life. It has good potential for rural employment generation.
Considering all the options in India, Jatropha Curcas has been identified as the most suitable source due to its lower gestation period. While the seeds are used for oil extraction, other parts of the plant, that is, leaves, bark and the like, can be used for organic dyes, medicines, biogas and the like.
Originating in the Caribbean islands, jatropha has spread as a valuable hedge plant to Africa, Asia and India. It grows in a variety of agro-climatic conditions. Thus it ensures a reasonable production of seeds with little inputs.
Intercropping
Intercropping of jatropha with lemon grass, turmeric, ashwagandha and the like has been found to be an economically viable option when compared with monocropping. Since jatropha is not suitable for forage, fence farming is also an attractive option. Plantation of saplings from the seeds rather than vegetative propagation is a better option for the dry areas.
The plantation of saplings (4 months old) should be carried out before the rains. As the growth and canopy coverage are more in fertile soil, the plants occupy more area when compared with dry land cultivation.
While the plantation pitch for jatropha could be 1.5 x 1.5m in lighter/dry lands, a spacing of 2.0 x 2.0m would be required in fertile soil resulting in 2,500 plants/hectare.
For intercropping, a spacing of 3m should be maintained between the rows for inter-cultivation and ploughing required for vegetables and flowers. For better growth, the plants require irrigation for the first two years. The plants require pruning after they grow over 1.0 m in height.
Effective yield
The jatropha plant bears fruits from the 2nd year after its plantation and the economic yield stabilises from the 4th or 5th year onwards. The plant may live for more than 50 years with an average effective yielding time of 50 years.
The economic yield can be considered as 0.75-2.00kg/plant and 4.00-6.00 tonnes per hectare per year depending on the agro-climatic zone and agricultural practices.
The cost of plantation has been estimated as Rs.20,000 a hectare, inclusive of plant material, maintenance for one year, training, overheads and the like.
A selling price of jatropha seeds at Rs.12 a kg would be an economically attractive proposition for farmers.
Oil from jatropha seeds (oil content: 35 per cent on average) can be extracted by using a screw press for further processing into biodiesel by the transesterification route. Transesterification is the process of converting the raw vegetable oil into biodiesel.
The process involves displacement of alcohol from an ester by another alcohol (methanol is used commonly).
Return on investment
For an optimal capacity of 10,000 TPA of biodiesel, the capital cost for oil extraction and transesterification would be Rs.20,000/tonne capacity. The return on investment (ROI) has been arrived at 15 per cent pre tax on the capital cost.
The efficient storage of biodiesel resources can provide energy security to the country. Biodiesel can safely be stored for up to 6 months. The existing storage facilities and infrastructure for petrol and diesel can be used for the biodiesel with minor alterations.
12 million jobs
India has vast stretches of degraded land, mostly in areas with adverse agro-climatic conditions, where species of jatropha can be grown easily. Considering 10 million plantation on both sides along the railway tracks, 1,26,000 hectares can be cultivated with jatropha.
Use of 11 million hectares of wasteland for jatropha cultivation can lead to generation of a minimum of 12 million jobs.
Production of bio-fuel from plant materials is a major step toward harnessing one of the world's most-prevalent, yet least-utilised renewable energy resources.
India, with its huge waste/non-fertile lands, has taken a well-noted lead in jatropha cultivation and commercial production is what the industries have to focus on for sustainable development.
SOUMITRA BISWAS G.SRIKANTH
& NIRMALA KAUSHIK
Technology Information, Forecasting and Assessment Council (TIFAC)
Department of Science & Technology, New Delhi
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