India's58' consumption ofenergy today is at 6500TWha-1, but this is expected to double in the near future. Today, about 2.5 Mio biogas plants are running, with an average size of 3-10 m3 ofdigester volume. Depending on the substrate, the plants generate 3-10 m3 biogas per day, enough to supply an average farmer family with energy for cooking, heating, and lighting.
The national advisory board for energy in India has published a report forecasting the required quantity and the manner of supply of energy in the future. The board estimates that India has enough resources to sustain 16-22 Mio small biogas plants with 2 m2 reactor volumes, each to supply sufficient energy for a farmer family with 4 cows. The estimates suggest that the plants will together provide an energy yield that corresponds to 13.4 Mio Mg of kerosene oil. The amount of fertilizer is projected at 4.4 MioMg.
In plants in India, the substrate, cattle dung, and biogenous waste, are manually mixed with water in a ratio of 10% dry matter to 90% water. The mix is filled into the digester by simply pushing. The reactor is neither heated nor isolated, enabling the fermentation process to take place at temperatures in the the region of 14 °C during winter and 25 2 C during summer. In the reactor itself, the substrate is mixed by a simple mixer which is operated manually. After a dwell time of the substrate in the reactor of around 100 days the fermented residue is removed with buckets or scoops. Pumping systems are not used.
In general, such a small biogas plant costs around 5000 Indian rupees (about 120 US$) per cubic meter of digester. The plants are constructed with the help of local artisans who receive a daily wage of 50 rupees (1.20 US$).
The construction of more and more biogas plants has revealed several beneficial side effects, such as a significant reduction in the exhaustive cultivation of forests. Unexpected successes were noted in the medical sector also. Since respiratory systems and eyes were no longer exposed to aggressive wood smoke from fires, the number of cases of acute asthma and eye diseases was significantly reduced.
Overall, the use of biogas for energy supply provides economic but also ecological and hygienic advantages.
Figure 4.3 Biogas plants. China: cross section of a "four in one" plant in China (1st row, left), "Four in one" plant in China (1st row, right)
Green house in China, part of a "Four in one" plant (2nd row, left), pig pen with loophole to digester and digester cover in the floor (2nd row, right)
Figure 4.3 Biogas plants. China: cross section of a "four in one" plant in China (1st row, left), "Four in one" plant in China (1st row, right)
Green house in China, part of a "Four in one" plant (2nd row, left), pig pen with loophole to digester and digester cover in the floor (2nd row, right)
Plastic biogas reactor in South Africa (3rd row, left), Moderm biogas plant in Kerala, India, (Suntechnics GmbH) producing 6.75 kW to lighten street-lamps (3^ row, right), Feeding of a biogas plant in Peru (4* row, left), Bioreactors in the Ukraine (Elenovka/ Dnipropetrovsk).
The national advisory board for energy in India has published a report forecasting the required quantity and the manner of supply of energy in the future. The board estimates that India has enough resources to sustain 16-22 Mio small biogas plants with 2 m2 reactor volumes, each to supply sufficient energy for a farmer family with 4 cows. The estimates suggest that the plants will together provide an energy yield that corresponds to 13.4 Mio Mg of kerosene oil. The amount of fertilizer is projected at 4.4 MioMg.
In plants in India, the substrate, cattle dung, and biogenous waste, are manually mixed with water in a ratio of 10% dry matter to 90% water. The mix is filled into the digester by simply pushing. The reactor is neither heated nor isolated, enabling the fermentation process to take place at temperatures in the the region of 14 °C during winter and 25 2 C during summer. In the reactor itself, the substrate is mixed by a simple mixer which is operated manually. After a dwell time of the substrate in the reactor of around 100 days the fermented residue is removed with buckets or scoops. Pumping systems are not used.
In general, such a small biogas plant costs around 5000 Indian rupees (about 120 US$) per cubic meter of digester. The plants are constructed with the help of local artisans who receive a daily wage of 50 rupees (1.20 US$).
The construction of more and more biogas plants has revealed several beneficial side effects, such as a significant reduction in the exhaustive cultivation of forests. Unexpected successes were noted in the medical sector also. Since respiratory systems and eyes were no longer exposed to aggressive wood smoke from fires, the number of cases of acute asthma and eye diseases was significantly reduced.
Overall, the use of biogas for energy supply provides economic but also ecological and hygienic advantages.
Figure 4.3 Biogas plants. China: cross section of a "four in one" plant in China (1st row, left), "Four in one" plant in China (1st row, right)Green house in China, part of a "Four in one" plant (2nd row, left), pig pen with loophole to digester and digester cover in the floor (2nd row, right)
Figure 4.3 Biogas plants. China: cross section of a "four in one" plant in China (1st row, left), "Four in one" plant in China (1st row, right)
Green house in China, part of a "Four in one" plant (2nd row, left), pig pen with loophole to digester and digester cover in the floor (2nd row, right)
Plastic biogas reactor in South Africa (3rd row, left), Moderm biogas plant in Kerala, India, (Suntechnics GmbH) producing 6.75 kW to lighten street-lamps (3^ row, right), Feeding of a biogas plant in Peru (4* row, left), Bioreactors in the Ukraine (Elenovka/ Dnipropetrovsk).
ARTI has developed a compact biogas plant which uses waste food rather than dung/manure as feedstock, to supply biogas for cooking. The plant is sufficiently compact to be used by urban households, and about 2000 are currently in use – both in urban and rural households in Maharashtra. A few have been installed in other parts of India and even elsewhere in the world. The design and development of this simple, yet powerful technology for the people, has won ARTI the 
Most biogas plants which are currently in operation in India and elsewhere are designed for animal manure as their main feedstock, and are therefore used in rural areas. Whereas in cities, a majority of the people use LPG or kerosene for cooking. The immediate benefit from owning a compact biogas system is the savings in cost as compared to the use of kerosene or LPG for cooking. The up-front cost of a biogas system is higher than for LPG, since an LPG bottle plus a two burner stove costs only INR 5,000 (spprox. USD 100) whereas the compact biogas plan plus a biogas stove costs about INR 10,000 (approx. USD 200). However, the operational cost for biogas is only about INR 2 per day if waste flour is used as feedstock, and can be zero if the plant uses only food wastes. This is much cheaper than LPG, which costs about INR 30 per day, even with the current subsidy of 50%. Biogas can easily replace 50% of the LPG used by a family. Some families who use a pressure cooker for cooking and collect food waste from their neighbours have replaced all their LPG use.
In cities, waste food is often discarded and its rising heap attracts flies and rodents, thus creating a public health hazard. The compact biogas plant technology developed by ARTI readily accepts highly digestible organic materials such kitchen waste as feedstock and can easily blend into the urban lifestyle. A single plant produces sufficient biogas to at least halve the use of LPG or kerosene for cooking in a household, as well as a small amount of solid residue which can be used as fertiliser. ARTI’s compact biogas plant could be replicated anywhere where there is the space for the plant, and the temperature is sufficiently high.
People continue to do this in cities but there are fewer animals to consume it. The result is that smelly, rotting food attracts flies and rats. Some authorities collect food waste and dispose of it in landfill. Here again, available land space presents its own constraints. For example: the authority in Pune has decided it can no longer dispose city waste in a landfill because of lack of space, and local officials are therefore strongly encouraging the use of biogas plants to dispose of food waste. Local council offices have set up demonstration plants, which use local food wastes and provide gas for making tea for local officials and their visitors. 
ARTI’s trained technicians install the biogas plants using locally available plastic tanks (commonly used for water storage) and a plumbing kit supplied by Samuchit Enviro-Tech (SET) Pvt. Ltd., a company set up by members of ARTI. SET also supplies a single burned biogas stove made of cast iron, and a gas cock. This set, consisting of the plumbing kit and a single burner biogas stove, costs INR 2350 (M.R.P. inclusive of taxes and transport anywhere in India). The total estimated cost of the compact biogas system for a typical household (around 1000-1500 lit capacity) is about INR 10,000, but the actual cost may vary based on local prices of plastic tanks and local labour costs. 
