Agriculture is probably the only industry in which 60-75 per cent of the product is simply junked. A farmer is able to see only 25-40 per cent of his crop (grain, fruits etc.) The rest is totally wasted and most of the times burnt in the fields.
Energy produced from crop residues can be a viable option especially for agricultural countries such as India. Of the 600-1000 million tonnes of agricultural residues produced in India every year, most of it is burnt.
If sufficient amount of crop residue is used for energy production, it will reduce India’s dependence on oil import and improve the profitability of the farming sector, provide rural wealth and create employment. On an average a farmer can make extra income of Rs. 2000-4000/acre if his crop residue is used to produce energy for powering India.
Techniques
Techniques that can be adopted for using crop residues for energy are:
Combustion (direct burning and co-firing)
In this method residues are simply burnt and the heat produced is used for cooking or production of electricity.
Non-combustion methods (thermo-chemical, biochemical etc.)
Here the crop residues are mixed with coal to burn in power plants. Burning crop residues with coal not only lowers operational costs but results in greater reductions of harmful emissions. Non-combustion methods can be used to convert crops residues into gaseous, liquid, or solid fuels that can be used directly in a power plant for energy generation.
Three types of energy
Crop residues can be used to produce three types of energy. Liquid fuels such as ethanol or pyrolysis oil; gaseous fuels like biogas (methane) and electricity.
Canada, Japan and U.S. have already set up ethanol fuel plants though research is still in progress on how to make ethanol production from residues economically viable and environmentally sound. Theoretically the residues in India can produce 156 billion liters of ethanol, which can take care of 42 per cent of India’s oil demand by 2012.
Canada, U.S.A. and China have been set up Pyrolysis oil plants and are producing oil from various agriculture residues. India can produce about 400 billion kg of pyrolysis oil from its agricultural residues which is equivalent to 80 per cent of India’s total oil demands for 2012.
These residues can also produce 80,000 MW of electric power, or nearly 60 per cent of the present installed capacity of the country, round the year through biomass-based power plants. The technology for this is very mature and there are thousands of such plants running all over the world.
This video gives an introduction to a project promoting the use of biomass burning stoves in India.
