Biogas is primarily methane that is generated from an anaerobic digestion of organic wastes by microorganisms. It is a relatively simple and economical method to produce a fuel from waste.
While technically biogas can be produced from any type of organic material, most times, biogas is produced from organic waste. This waste could comprise agricultural and crop waste, human waste and animal waste (cow dung for instance). With a calorific value of about 5000 KCal / m3, biogas is an excellent fuel for heating purposes as well as for generating electricity.
It is estimated that India can produce power of about 17,000 MW using biogas. This is about 10% of the total electricity installed capacity in India.
Biogas in households and communities
Biogas production has been quite dominant in India at household and community levels (especially in rural areas) than on large scales. In villages especially, thousands of small biogas plants use the cattle waste (especially cow dung) and provide biogas used for home heating and cooking. It is estimated that over 1.8 million such biogas plants have been installed all over India.
Such use of biogas systems in agrarian communities can increase agricultural productivity. This is because producing heat using biogas is more efficient than producing it using combustion, and hence more agricultural and animal waste can be returned to the land by farmers as organic fertilizer. Moreover, the slurry that is returned after methanogenesis is superior in terms of its nutrient content and can be used a soil and plant nutrient.
Biogas for electricity production
The use of biogas for electricity generation in India is more recent, but this trend is accelerating. In many cities across India, sewage treatment centers and organic waste treatment plants (those treating organic municipal solid waste, for instance) already use anaerobic digesters to generate biogas and electricity. Many of these require sizable investments, but it is estimated that they have a good return on investment as the main feedstock that they use is essentially free.
Biogas in the Indian industry
Use of digesters at industrial complexes (to treat the waste generated at the factory) is also increasing. For the factories and businesses concerned, this is an excellent avenue to dispose of waste in a cost effective manner while at the same time generate heat and/or electricity. Industries that have an especially high potential for using anaerobic digestion include catlle and poultry industry, sugar, breweries, pulp and paper, leather, and the fruits & vegetables industry.
Future prospects for biogas in India
With the Indian government keen on utilizing renewable resources for energy production, it is likely that there will be a greater thrust and higher incentives for concepts such as biogas production from waste. An increasing awareness among the public regarding sustainable use of resources will only enhance the production and use of biogas. It can hence be expected that biogas will have a significant growth in India at all levels of usage (household, municipality and industry) for both heat generation and electricity production.