Energy security is as critical for agriculture as for any other economic activity. A good deal of plants’ energy requirement for growth and bearing grain or fruit is met directly by sunlight. But the use of commercial energy is also essential for modern agriculture in several ways — as a source of draught power, or in the form of inputs like irrigation, fertilisers and chemicals, or even for post-harvest handling, storage, transportation and processing.
At present, though the farm sector contributes nearly 18 per cent to India’s gross domestic product (GDP), it accounts for only 7.4 per cent of commercial energy consumption. But this is bound to change, thanks to the growing mechanisation of farm operations, replacing humans and animals with machines.
Studies have shown that, between 1970 and 2005, the share of animal power in agricultural operations fell from 44 per cent to just 6 per cent and that of manual power from 37 per cent to 8 per cent. Much of this has been substituted with electricity and petroleum products, notably diesel. Though tractors consume a lot of energy, they are emerging as a significant means of delivering power for farm operations as well as for transportation and running irrigation pumps. This trend is expected to continue.
The real worry today is as much about how to meet the growing demand for energy as about how to remove inefficiencies in energy use, which are resulting in a substantial waste of this precious and scarce resource.
According to the director general of the Indian Council of Agricultural Research (ICAR) S Ayyappan, most pump sets in operation use electric motors of poor efficiency, which results in higher consumption of electricity for delivering the same or lower output. “Replacement of even 10 per cent of the existing 15.35 million electrical pump sets with more efficient ones would result in a saving of about 4 billion kilowatt (Kw) hours of power per year, equivalent to about 900 megawatt (Mw) of generation capacity,” he said.
There is also scope for saving fuel consumed by tractors. This can be done by avoiding the use of heavier tractors for relatively lighter farm operations. There are numerous instances in which farmers use tractors of as much as 35 horsepower (HP) to perform minor operations like running a grain thresher, which requires only a 7.5 to 15 HP diesel engine to operate, or for energising a 5 to 10 hp electric motor. However, much of this wasteful use of tractors can be attributed to the non-availability of electric power in rural areas in adequate measure, at the time when it is required for agricultural work. If this aspect can be taken care of, the indiscriminate use of tractors can be curtailed.
However, such inept use of energy notwithstanding, the availability of commercial energy for the farm sector will have to be enhanced considerably. Ayyappan maintains that the use of power in agriculture would have to rise from the present 1.6 Kw per hectare to 2.5 Kw to meet production targets in the next 20 years.
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Renewable energy sources, such as sun, wind and biomass, which are plentiful in India, will have to play a greater role in meeting the increased energy demand of the farm sector. Biomass, chiefly agricultural waste, can be an important raw material for decentralised power generation in the rural belt. Going by Ayyappan’s estimates, about 590 million tonne of agricultural waste and agro-industrial residues are generated annually in the country. These can be conveniently used to generate thermal or electric energy for the farm sector.
Deploying efficient ways and means of applying fertilisers and supplying irrigation water to crops can lead to a substantial energy saving in agriculture. The production of one kg of nitrogen fertiliser, for instance, needs as much as 78,000 kilo Joule (kJ) of energy. Improved methods of application to prevent fertiliser loss through gasification in the form of ammonia or leaching down to below the plants’ root-zones can help reduce fertiliser demand, which, in turn, can save energy that would otherwise be used to manufacture fertilisers. Similarly, the use of more efficient means of irrigation that can cut water losses can help save energy consumed in extracting water from its source and its conveyance to the plants. All these measures can contribute to energy security for the farm sector.