• Introduction
• Profile
• Livestock and Poultry Resources
• Methane Emissions from Manure Management
• Management of Livestock Waste in India
• Advantages of Using Biogas as a Fuel Source
• Biogas Production
• Indian Policy Framework for Biogas Plants
• Technology Designs of Family Type Biogas Plants
• Status of Biogas Plants
• Case Studies
• Link to M2M Website - Agriculture

Introduction

The primary sources of methane emissions from agriculture are livestock enteric fermentation, livestock waste management, rice cultivation, and agricultural waste burning. Of these, livestock waste management offers the most viable, near-term opportunities for methane recovery and utilisation.

Methane released from manure management systems can be captured and used as clean energy to produce electricity or to fuel gas-fired equipment such as engines, boilers, or chillers, which can meet part of a farm's energy requirements. Proven techniques for recovery include covered anaerobic lagoons and a variety of anaerobic digester designs. Farms can achieve environmental benefits related to improved livestock waste management.

Profile

The agriculture sector in India contributes over 20% to the GDP. Small farms dominate the sector, and the main agricultural products are rice, wheat, course cereals, oilseeds, pulses, cotton and jute. Productivity is generally low and is unevenly distributed among States. The sector provides employment to more than 55% of the country's workforce and livelihood security to about 650 million people.

The livestock sector contributes around 6.8% to GDP and employs 8% of the labour force. The contribution of the livestock sub-sector to agricultural GDP has increased by in the last twenty years, from less than 15% in the late 70s to over 33% in 2002. The major contribution to GDP comes from the cattle and buffaloes of nearly 80%, the balance being poultry, pigs, sheep and goats.

(Source: Livestock Sector Brief: FAO; July 2005)

Some of indicators of Indian agriculture 2001-02 and 2002-03, are as below

* 2002-03 was a drought year

(Source: Directorate of Economics and Statistics, Government of India )

Livestock and Poultry Resources

India being an agriculture dominated country the livestock sector has a significant role in the in the Indian farming system. Livestock provides for milk, meat, farmyard manure, wool, egg etc. Livestock is also extensively used in agriculture for draught purpose as well for transport. As per livestock census, the total number of livestock and poultry in the country are as under:

(Source: Department of Animal Husbandry. Dairying & Fisheries, Government of India )

Methane Emissions from Manure Management

Following table represents the methane emission from manure management, in five countries (USEPA data) in carbon dioxide equivalent, it also depicts the projected emission till 2020.

Methane emission from manure management (in million tonnes) carbon dioxide equivalent

(Source: USEPA)

India is the world's third largest emitter of methane. As per the USEPA study, methane production of carbon dioxide equivalent from rice cultivation in India during 2005 was 96.54 million tonnes compared to 223.92 million tonnes in China and world total of 671.89 million tonnes.

Management of Livestock Waste in India

In India livestock wastes are managed in the following three ways:

• The waste excreted by livestock (primarly cattle) is removed and dumped into heaps nearby the cattle sheds. The heaps are allowed to settle and eventually it gets converted into manure, which is subsequently utilized in fields as an organic matter.
• Livestock waste is utilised for supplying energy at village levels where the waste is made into small cakes and dried and later on used as a fuel for cooking.
• The third method, which is being popularized both by central and state government is the establishment of biogas plant where waste is used for the production of biogas (biogas consists of methane (CH 4 ), carbon dioxide (CO 2 ) and traces of other gases such as hydrogen (H 2 ), carbon monoxide (CO), nitrogen (N 2 ), oxygen (O 2 ) and hydrogen sulfide (H 2 S).) under anaerobic conditions. The gas is used for cooking purpose and the slurry after methane extraction is used as farm manure.

Advantages of Using Biogas as a Fuel Source

• Biogas can be used as a fuel for cooking and lighting purposes. It can also be used in diesel engines to substitute diesel-oil up to 80%. Biogas engines are also available in the market. Since the decomposed slurry, is a good source of manure for agricultural lands, biogas plants help in total recycling of organic waste.
• Biogas can be used as an excellent fuel for many applications including power generation. Biogas plants offer a very useful source of decentralized energy supply based on local resources. Cooking through biogas reduces consumption of fuel wood, dung cake, agricultural wastes, coal or kerosene.
• Use of biogas as cooking fuel provides an efficient way of converting fuels to heat and reduces indoor air pollution. The other environmental benefits include improved waste management, reduced emission of methane to the atmosphere and reduction in deforestation.
• As per the reports of the Ministry of New and Renewable Energy, Government of India, studies have shown that the digested slurry obtained from biogas plants contains 80% carbon, 1.8% nitrogen, 1% phosphorous and 0.9% potash making it an excellent source of not only humus but also micronutrients for crops. Substitution of inorganic fertilizer by biogas slurry helps towards organic farming.

Biogas Production

The most popular and technically mature anaerobic digestion systems are those designed for the digestion of animal wastes. The biogas sector in India has been expanding to include the use of new feed stocks such as kitchen wastes, by-products from food processing industries, agricultural residues, market wastes, garden wastes and other biomasses, sewage sludge, municipal wastes etc. A number of advanced designs have been developed for effectively treating these wastes to produce biogas, deodorize the process, disinfect and stabilize the digestible product.

In recent years, with the objective of disposal of various organic wastes in an environment friendly manner, the interest in setting up biogas plants has increased. However the initial investments for such projects are considered to be high when compared to the power generating projects based on conventional fuels. The purpose of these projects, therefore is not to generate energy alone but to dispose off wastes.

Indian Policy Framework for Biogas Plants

The Ministry of New and Renewable Energy, Government of India has a centrally sponsored programme - National Project on Biogas Development, which was launched in 1981-82. It was renamed as National Biogas and Manure Management Programme (NBMMP) in 2002-03 for implementation during the Tenth Plan. The Programme promotes indigenously developed simple-to-construct and easy-to-operate family type biogas plants. Following are the objectives:

• To provide fuel for cooking purpose and organic manure to rural households through family type biogas plants
  
• To mitigate drudgery of rural women, reduce pressure on forests and accentuate social benefits; and
  
• To improve sanitation in villages by linking sanitary toilets with biogas plants

The programme recommends the following technology designs:

Technology Designs of Family Type Biogas Plants

• Floating Drum Plants (KVIC) having digester made of bricks or stone masonry and gas holder made of ferro-cement digester of fiber-glass reinforced plastic or different combinations of the above.
• Fixed dome design called Deshbandhu Model made of brick masonry or ferro-cement with in-situ construction technique.
• Fixed dome model made of pre-fabricated reinforced cement concrete

Status of Biogas Plants

According to the 2007-08 Annual Report of Ministry of New and Renewable Energy (MNRE) 52,159 biogas plants of the approved models under the National Biogas and Manure Management Programme (NBMMP), were installed across the country with the financial support of the MNRE. The cumulative installation according to the report is 38.90 lakh in all States and Union Territories .

(Source: Annual Report 2007-2008 of Ministry of New and Renewable Energy, GoI)

Case Studies

This section provides descriptions of a few methane recovery and utilization projects being implemented in the agriculture and livestock sector in India. For more details please click here.

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