A significant fall-out of the sharp rise in petroleum prices is the renewed interest globally in looking for alternatives. Fortunately, several options are available for substituting at least some petrol and diesel consumption in automobiles with bio-fuels.
Brazil has for nearly three decades been blending petrol with ethanol made from sugarcane. Some countries are using other crops, including grains, for producing alcohol that gets mixed with petrol. Similarly, bio-fuel for diesel engines can be produced from most vegetable oils, though non-edible oils are generally preferred for obvious reasons.
This, however, requires setting up plants for extracting oil from seeds and for subjecting it to the chemical process called transesterification. In fact this process yields by-products, like glycerine and oil cake, that can also be put to gainful use.
It is no wonder then that governments the world over have begun encouraging the cultivation of plant species suitable for generating bio-fuel. India is no exception, though the level of interest that many other countries display in this field is still lacking here.
Nevertheless, there certainly is the realisation that at the current prices of petroleum products, the use of bio-fuel makes eminent sense.
As such, the programme for selling ethanol-blended petrol in nine states, which had run into trouble because of the failure of the petroleum companies and the sugar industry to reach agreement on the pricing of molasses-based ethanol, is being revived again. Today, even a relatively high price may be acceptable to the petroleum industry.
The plants being deemed suitable for producing bio-diesel in India include jatropha and pongamia. However, jatropha seems to have emerged as the preferred species for several reasons. It has a high oil content of over 30 per cent and the plant, being a bush, is easy to manage.
Besides, it begins bearing seed in about four years, against the much longer time taken by some other plants. In fact, several states are going ahead with large-scale plantation of jatropha on lands not ideally suitable for the cultivation of commercial crops. As a result, a British firm has come forward to set up a plant in Tamil Nadu for producing bio-diesel from jatropha.
There are several merits in encouraging the large-scale production and consumption of bio-fuels, but there are some concerns as well. On the positive side, bio-fuels are produced from renewable sources and are environment-friendly.
The carbon dioxide produced by burning bio-fuels is the same that the plants had imbibed from the atmosphere during their growth and does not, therefore, add to the existing carbon load of the atmosphere.
However, their other effects on the environment are yet to be fully perceived. The danger of untoward ecological consequences following their large-scale adoption on plantations cannot be ruled out at this stage. Sugarcane, for instance, is a water-gulping crop and can impact hydrology.
Other concerns include the problems that might emerge at the stage of disposal of by-products, for which there may not be adequate demand. In the case of pongamia, certainly, there is every danger of its overwhelming other plant species if included in agro-forestry.
This is because it produces root suckers that can spread laterally up to several metres in the soil. Such concerns need to be considered and addressed before going the whole hog for all manner of bio-fuels.