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 over 10% of the total electricity installed capacity in India.
The advantages of biogas-based energy generation are as follows:
1. It is based on renewable sources
2. It can provide distributed energy generation, thereby providing much-needed energy for remote locations and villages.
3. In many cases, it provides a beneficial way of disposing organic waste
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 2 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 as a soil conditioner and plant nutrient (fertilizer).
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. Some of the industries that generate significant amounts of solid or liquid organic waste also have installed digesters and gas engines for electricity production. 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 cattle and poultry industry, sugar, breweries, pulp and paper, leather, and the fruits & vegetables industry. As pointed out earlier, some of these industries are already producing electricity from biogas, and this trend is likely to grow further in future.
Many Indian industries, in their quest for becoming more environment conscious, are turning to biogas one of their energy sources. In Sep 2009, for instance, PepsiCo India, a division of PepsiCo installed a biogas plant at its Pune-based Frito-Lay manufacturing unit. It’s the first plant within Frito-Lay’s global operations to use biogas. Companies such as Sintex Industries have introduced novel biogas digesters for the small users of this renewable energy resource.
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.
It is also possible to earn carbon credits for biogas-based power or heat generation in India. For instance, in Apr 2008, Andhyodaya, a non-government agency working in the field of promoting water management and non-conventional energy and social development distributed the first installment of the biogas carbon credit to farmers in the state of Kerala. Andhyodaya had helped construct 15,000 biogas plants in the state and earned carbon credits. This trend is likely to grow further.
Both the central and the state governments in India have recognized the significance of biomass-based energy in the context of development of the rural population. It is also heartening to note that steps are already being taken in this regard. For instance, in Feb 2010, the Haryana Government has formulated a Rs. 85 crore project for setting up 50,000 family size biogas plants to harness the potential of generating biogas for cooking and (remnants as) organic manure in the fields.
More such investments and efforts are on the horizon.
In sum, India has significant potential for generating heat and electricity from waste in the form of biogas. While only a portion of the potential has been tapped, it is likely that more investments in this direction could accelerate exploitation of this source in future.