The Holy Cow: Benefits of Biogas

Technologies » Biogas

Benefits of biogas

Biogas technology makes optimal utilization
of the valuable natural resource of dung;
it provides nearly three times more
useful energy that dung directly burnt,
and also produces
nutrient-rich manure.

As a cooking fuel, it is cheap and
extremely convenient. Based on the
effective heat produced, a 2cu m biogas
plant could replace, in a month, fuel
equivalent of 26 kg if LPG (nearly
two standard cylinders), or 37 litres
of kerosene, or 88kg of charcoal, or 210 kg
of fuelwood, or 740 kg of animal dung.
In terms of cost, biogas is cheaper, on a life cycle basis, than conventional biomass fuels (dung, fuelwood, crop wastes, etc.) as well as LPG, and is only fractionally more expensive than kerosene; the commercial fuels like kerosene and LPG, however, have severe supply constraints in the rural areas.

Benefits of biogas

To the housewife, a biogas is easy to use and saves time in the kitchen; biogas stove has an efficiency of about 55% which is comparable to that of an LPG stove. Cooking on biogas is free from smoke and soot, and can substantially reduce the health problems, which are otherwise quite common in most rural areas in India where biomass is the chief source of fuel . The use of biogas is helpful to improve the quality of life in household.

However, the use of biogas is by no means confined to cooking alone. It can be used, through a specially designed mantle, for lightning, too. Further, biogas can partially replace diesel to run IC (internal combustion) engines for water pumping; small industries like floor mill, saw mill, oil mill etc. This would not only reduce dependence on diesel, but also help in reducing carbon pollutants which adversely affect the atmosphere. Dual – fuel engines (80% biogas and 20% diesel) are now commercially manufactured in India. Biogas can be similarly used to produce electricity, though this has not been attempted on a large scale in the country so far. Nevertheless, the versatility of biogas is its greatest advantage as a source of energy for the rural areas.

While biogas has multiple benefits at the individual family level, it also has several qualitative and quantitative benefits at the societal level. Firstly, a shift to biogas from traditional biomass fuels results in less dependence on natural resources such as forests, in less dependence on natural resources such as forests, checking their indiscriminate and unsustainable exploitation. Since dung is collected systematically when used in biogas, environment can be kept clean and hygienic.

The other advantage is that, unlike centralized systems such as thermal power plants and fertilizer factories, which entail huge capital investments and need elaborate distribution networks, biogas plants are decentralized systems which can be installed even in remote areas with very low investments.

Potential of biogas

In India, the dissemination of large–scale biogas plants has began in the mid-seventies and the process has become consolidated with the advent of the National Project on Biogas Development (NPBD) in 1981, which has been continuing since. Against the estimated potential of 12 million biogas plants, 2.9 million family type and 2700 community, institutional and nightsoil-based plants have been set up till December 1999. This is estimated to have helped in a saving of 3 million tonnes of fuelwood per year and manure containing nitrogen equivalent to 0.7 million tonnes of urea.

However, in terms of total dung that is available in the country, the potential is much more. The bovine population in India is 260 millions. As adult bovine produces an average of 10 kg of dung per day. Since grazing is a common practice in India, all the dung produced cannot be collected. If it is assumed that 75% of the dung is collected, nearly 2 millions tonnes of dung would be available everyday. At 25 kg per one cubic metre, this dung can feed as many as 40 millions biogas plants of 2 cubic metre capacity, which can be considered the ultimate potential for biogas technology.

But even this high potential of biogas is based on animal dung only. However, all organic matter can technically be used to generate methane; if the scientific experiments that are going on in the country under the patronage of MNES to develop alternative feedstocks (such as water hyacinth, kitchen waste, and poultry waste) come to fruition, potential for biogas generation could be virtually unlimited. It can be mentioned in this context that human waste is an excellent source of biogas which would enhance the potential; substantially. With such high potential, which can be routed to hitherto unemphasized applications of shaft power and electricity generation, biogas can make a significant contribution to the development of small industries and agriculture, and thus to the overall advancement of the rural areas.

Biogas plant models