Biogas

Government of IndiaMinistry of Non-Conventional Energy Sources 1

Dr Manmohan SinghPrime Minister of India

‘Energy is an important input for

economic development. Since

exhaustible energy sources in the

country are limited, there is an

urgent need to focus attention on

development of renewable

energy sources and use of energy

efficient technologies. The

exploitation and development of

various forms of energy and

making energy available at

affordable rates is one of our major

thrust areas.’

Smt. Sonia GandhiChairperson, National Advisory Council

‘Today India is one of the few

leading countries in the

development and utilization of

renewable energy. The country is

blessed with various sources of

non-conventional energy and I

hope the efforts of Ministry of

Non-Conventional Energy

Sources will promote viable

technologies that can reach the

benefits of such sources to the

poorest people in the far-flung

regions of the country.’

Renewable Energy in India

Energy is a basic requirement for economic development. Everysector of Indian economy – agriculture, industry, t r a n s p o r t ,commercial, and domestic – needs inputs of energy. The

economic development plans implemented since independence havenecessarily required increasing amounts of energy. As a result,consumption of energy in all forms has been steadily rising all over thecountry.

This growing consumption of energy has also resulted in the countrybecoming increasingly dependent on fossil fuels such as coal and oiland gas. Rising prices of oil and gas and potential shortages in futurelead to concerns about the security of energy supply needed to sustainour economic growth. Increased use of fossil fuels also causesenvironmental problems both locally and globally.

Against this background, the country urgently needs to develop asustainable path of energy development. Promotion of energyconservation and increased use of renewable energy sources are thetwin planks of a sustainable energysupply.

Fortunately, India is blessed witha variety of renewable energysources, the main ones beingbiomass, biogas, the sun, wind, andsmall hydro power. (Large hydropower is also renewable in nature,but has been utilized all over theworld for many decades, and isgenerally not included in the term‘new and renewable sources ofenergy’.) Municipal and industrialwastes can also be useful sources ofenergy, but are basically differentforms of biomass.

RE N E WA B L E E N E R GY IN IN D I A

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Advantages of renewable energy are that it isperennialavailable locally and does not need elaborate arrangements fortransportusually modular in nature, i.e. small-scale units and systems can bealmost as economical as large-scale onesenvironment-friendlywell suited for decentralized applications and use in remote areas.

The Ministry of Non-Conventional Energy Sources has beenimplementing comprehensive programmes for the development andutilization of various renewable energy sources in the country. As aresult of efforts made during the past quarter century, a number oftechnologies and devices have been developed and have becomecommercially available. These include biogas plants, improved woodstoves, solar water heaters, solar cookers, solar lanterns, street lights,pumps, wind electric generators, water-pumping wind mills, biomassgasifiers, and small hydro-electric generators. Energy technologies forthe future such as hydrogen, fuel cells, and bio-fuels are being activelydeveloped.

India is implementing one of the world’s largest programmes inrenewable energy. The country ranks second in the world in biogasutilization and fifth in wind power and photovoltaic production.Renewable sources already contribute to about 5% of the total power

generating capacity in thecountry. The majorrenewable energy sources anddevices in use in India arelisted in Table 1 along withtheir potential and presentstatus in terms of the numberof instal lations or totalcapacity.

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RE N E W A B L E E N E R G Y IN IN D I A

Renewable energy in India at a glance

CumulativeEstimated installed capacity /

Source/System potential number*

Wind power 45 000 MW 3595 MW

Biomass power 16 000 MW 302.53 MW

Bagasse cogeneration 3500 MW 447.00 MW

Small hydro (up to 25 MW) 15 000 MW 1705.63 MW

Waste to energyP Municipal solid waste 1700 MW 17 MWP Industrial waste 1000 MW 29.50 MW

Family-size biogas plants 12 million 3.71 million

Improved chulhas 120 million 35.20 million

Solar street lighting systems — 54 795

Home lighting systems — 342 607

Solar lanterns — 560 295

Solar photovoltaic power plants — 1566 kWp

Solar water heating systems 140 million m2 1 million m2 ofof collector area collector area

Box-type solar cookers — 575 000

Solar photovoltaic pumps — 6818

Wind pumps — 1087

Biomass gasifiers — 66.35 MW

* as on 31 March 2005

Table 1

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NAT I O N AL EL E C T R I C I T Y PO L I C Y 2005

National Electricity Policy 2005

The National Electricity Policy aims at achieving the followingobjectives.

1 Access to Electricity – available for all households in the next fiveyears.

2 Availability of Power – demand to be fully met by 2012. Energyand peaking shortages to be overcome and spinning reserve to beavailable.

3 Supply of reliable and quality power of specified standards in anefficient manner and at reasonable rates.

4 Per capita availability of electricity to be increased to over 1000units by 2012.

5 Minimum lifeline consumption of 1 unit/household/day as a meritgood by 2012.

6 Financial turnaround and commercial viability of electricity sector.7 Protection of consumers’ interests.

The Electricity Act 2003

The Electricity Act contains the following provisions pertaining to non-conventional energy sources.

Sections 3(1) and 3(2)

Under Sections 3(1) and 3(2), it has been stated that the CentralGovernment shall, from time to time, prepare and publish the NationalElectricity Policy and Tariff Policy, in consultation with the stategovernments and authority for development of the power system basedon optimal utilization of resources such as coal, natural gas, nuclearsubstances or material, hydro and renewable sources of energy.

Section 4

Section 4 states that the Central Government shall, after consultationwith the state governments, prepare and notify a national policy,permitting stand-alone systems (including those based on renewablesources of energy and other non-conventional sources of energy) forrural areas.

Section 61

Section 61, 61(h) and 61(i) state that the appropriate commission shall,subject to the provision of this Act, specify the terms and conditionsfor the determination of tariff, and in doing so, shall be guided by thefollowing, namely, the promotion of cogeneration and generation ofelectricity from renewable sources of energy; and the National ElectricityPolicy and Tariff Policy.

Section 86(1)

Section 86(1) and 86(1)(e) state that the state commissions shalldischarge the following functions, namely, promote cogeneration andgeneration of electricity from renewable sources of energy by providing,suitable measures for connectivity with the grid and sale of electricityto any person, and also specify, for purchase of electricity from suchsources, a percentage of the total consumption of electricity in the areaof a distribution license.

TH E EL E C T R I C I T Y AC T 2003

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Biogas represents an alternative sourceof energy, derived mainly from

organic wastes. In India, the use of biogasderived from animal waste, primarily cowdung, has been promoted for over threedecades now.

According to the 1997 Livestock Census,the cattle population in the country is about290 million. The estimated potential ofhousehold biogas plants based on animal waste in India is 12 million. TillDecember 2004, under the National Biogas Programme, over3.7 million biogas plants in the capacity of 1–6 m3 had been installed.Larger units have also been set up in many villages, farms, and cattle houses.The estimated biogas production from these plants is over3.5 million m3 per day, which is equivalent to a daily supply of about 2.2million m3 of natural gas.

These plants usually provide gas for cooking and lighting, the latterthrough specially designed mantles. By replacing up to 75%

Biogas

Utility of cattle dung through biogas plant

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of the diesel in dual-fuel engines with biogas, mechanical and electricalpower is also generated. Efforts are now under way to introduce small-capacity engines to efficiently generate electricity from biogas in adecentralized mode. Standardized models of biogas plants – suitablefor individual households and institutions/communities – are thusavailable.

Along with development of plants and related infrastructure, a largepool of skilled manpower has been trained and deployed for plantconstruction and maintenance. The technology involved – anaerobicdigestion – has been successfully extended to treat industrial and urbanwastes on a large scale. This holds potential as a solution to numerousenvironmental problems, including waste and manure handling, waterpollution, and carbon dioxide emission.

Biogas Technology

Biogas is a clean fuel produced through anaerobic digestion of a varietyof organic wastes: animal, agricultural, domestic, and industrial.Anaerobic digestion comprises three steps.

Decomposition (hydrolysis) of plant or animal matter to break downcomplex organic materials into simple organic substancesConversion of decomposed matter into organic acidsConversion of acids into methane gas

As the process temperature affects the rate of digestion, it should bemaintained in the mesophilic range (30 °C–40 °C) with an optimumof 35 °C. It is also possible to operate plants in the thermophilic range(55 °C–65 °C) under controlled conditions. Apart from temperature,the rate of biogas production also depends on factors such as thecarbon : nitrogen ratio, hydraulic retention time, solid concentration,and types of feedstock.

Biogas consists of methane, carbon dioxide, and traces of other gasessuch as hydrogen, carbon monoxide, nitrogen, oxygen, and hydrogensulphide. The gas mixture is saturated with water vapour and maycontain dust particles. The relative percentages of these gases dependon the quality of feed material and the process conditions. The

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percentage of methane in the gas determines its calorific value as theother constituents do not contribute to the energy content. Themethane content of biogas is appreciably high, at 60%. This providesa calorific value high enough to find use in many energy applications,including power generation. Table 1 provides a comparison of thecalorific values of various fuels.

Components of Biogas Plants

Mixing tank The feed material (dung) is collected in the mixingtank. Sufficient water is added and the material is thoroughly mixedtill a homogeneous slurry is formed.Inlet pipe The substrate is discharged into the digester throughthe inlet pipe/tank.Digester The slurry is fermented inside the digester and biogas isproduced through bacterial action.Gas holder or gas storage dome The biogas gets collected in the gasholder, which holds the gas until the time of consumption.Outlet pipe The digested slurry is discharged into the outlet tankeither through the outlet pipe or the opening provided in thedigester.Gas pipeline The gas pipeline carries the gas to the point ofutilization, such as a stove or lamp.

Comparison of the calorific values of various fuels

Fuel Calorific value (approximate)

Natural gas 8600 kcal per m3

Liquefied petroleum gas 10 800 kcal per kg

Kerosene 10 300 kcal per kg

Diesel 10 700 kcal per kg

Biogas 5000 kcal per m3

Table 1

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Types of Biogas Plants

Fixed-dome type

The fixed-dome biogas plantconsists of one lower segment(for the digester) and ahemisphere over it (for bothdigester and gas holder). Themixing tank is connected to thedigester by a 15-cm asbestoscement pipe. Through the outlet hole provided in the digester, theslurry is pushed into the outlet tank and overflows through anotherhole provided in the outlet tank.

Floating-drum type

The floating-drum biogas plantconsists of a deep well-shapedunderground digester connected byinlet and outlet pipes. A mild-steelgas storage drum, inverted overthe slurry, rises and falls around a guidepipe corresponding to theaccumulation and withdrawal of gas.

Bag type

Made of rubberized nylon fabric,the bag-type biogas plant is aportable unit, which canconveniently be placed at anylocation.

The appropriate model isselected on the basis oftechnical requirements such aslocation, distance between

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kitchen and cattle shed, availability of dung and water, preferences ofthe beneficiaries, and so on.

Table 2 lists the model household biogas plants and appliances approvedfor promotion under the National Biogas Programme.

Model household biogas plants/appliances approved for promotion underthe National Biogas Programme

Table 2

Model Design guidelines

Fixed-dome biogas plant

1 Deenbandhu model with brick Code of Practices (Second Revision),masonry IS 9478:1989 of the BIS, New Delhi

2 Deenbandhu ferrocement model MNES letter No.13-11/99-BG, datedwith in-situ technique 5 March 1999

3 Pre-fabricated RCC fixed-dome MNES letter No.13-10/96-BG, datedmodel 10 January 2002

Floating drum biogas plant

1 KVIC floating metal drum type Code of Practices (Second Revision),IS 9478:1989 of the BIS, New Delhi

2 KVIC type plant with ferrocement Code of Practices IS-12986:1990 ofdigester and fibre glass reinforced BIS, New Delhiplastic gas holder

3 Pragati model Code of Practices (Second Revision),IS 9478:1989 of the BIS, New Delhi

Bag-type biogas plant

Flexi model MNES letter No.7-39/89-BG dated14 July 1995

Appliances ISI marked (BIS code IS - 8749:1988) burners with minimum 55%thermal efficiency

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Standard Capacity

For family-type biogas plants, approved models are available for1–6 m3 and 1–10 m3 capacities for fixed-dome and floating-drumplants, respectively. The commonly used capacities of these models are1–4 m3.

Applications

Cooking Biogas can beused for cooking in aspecially designed burner. Abiogas plant of 2 m3

capacity is sufficient forproviding cooking fuel to afamily of four to five.Lighting Gas lamps can befuelled by biogas. To powera 100 candle lamp (60 W),the biogas required is 0.13 m3 per hour.Power generation Biogas can be used to operate a dual-fuel engineand can replace up to 75% of the diesel.

Biogas Digested Slurry

The use of biogas digested slurry as organic manure can supplementthe usage of chemical fertilizers. The effluent manure does not produceany odour and hence does notcreate any pollution. Thebiogas s lurry is r ich innitrogen, the essential nutrientfor plant growth. Moreover,this nitrogen is in water-solubleform and can be easi lyabsorbed by the plants.

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The biogas slurry can also be mixed with biomass and composted.The slurry being full of bacteria (which can break down vegetablematter) makes excellent composting material. When a large mass ofbiomass waste with high carbon : nitrogen ratio is available, the slurryhelps stimulate decomposition by acting as a nitrogen primer. Earthwormscould either be cultured in dry sludge or in a compost pit.

Benefits

Provides a non-polluting and renewable source of energyEfficient way of energy conversion (saves fuelwood)Saves women and children from drudgery of collection and carryingof firewood, exposure to smoke in the kitchen, and time consumedfor cooking and cleaning of utensilsProduces enriched organic manure, which can supplement chemicalfertilizersLeads to improvement in the environment, and sanitation andhygieneProvides a source for decentralized power generationLeads to employment generation in the rural areas

Efficiency of energy conversion from cattle dung

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Cost

The cost of installation varies according to the model and size of theplant. The average estimated cost of the most popular Deenbandhumodel is given in Table 3.

The cost of a biogas plant increases by about 30% in hilly areas andby 50%–60% in the north-eastern region of the country.

Cost-effectiveness

The lifespan of a biogas plant is estimated to be over 15 years. However,taking into account the utilization pattern, socio-economic aspects,and climatic factors, the practical average life of family-type biogasplants installed in the country may be estimated at about 10 years.Based on a life-cycle analysis, the cost estimated for generation of 1 m3

biogas from a family-type biogas plant isRs 3. A comparison ofcost with diesel andkerosene based onenergy value shows thatbiogas is cost-effective.It is estimated that theconstruction of 1million biogas plantsgenerates about 30

The average estimated cost of the most popular Deenbandhu model

Plant capacity Cost per plant

1 m3 Rs 5500

2 m3 Rs 9000

3 m3 Rs 10 500

4 m3 Rs 13 500

Table 3

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million man-days of employment for skilled and unskilled workers and1.2 million tonnes of organic manure per year. Anaerobic digestion ofcow dung and effective utilization of biogas also substantially contributeto the abatement of greenhouse gas emissions.

Strategy for Promoting the Technology

The MNES provides central financial assistance for construction andmaintenance of biogas plants, development of skilled manpower,training for use and maintenance, awareness creation, and support toimplementing agencies and technical centres for implementation ofthe programme.

Financial Incentives

Under the National Biogas Programme, central subsidy is availableto users of different categories and areas for setting up biogas plants(Table 4).

Provision of Loans

The Reserve Bank of India and the National Bank for Agriculture andRural Development (NABARD) support the biogas programme.Detailed guidelines are available with both commercial and cooperativebanks for financing family-type biogas plants under the AgriculturalPriority Area. NABARD provided automatic refinancing facility tocommercial banks for loan amounts disbursed for biogas plants.

Repair and Servicing Facility

The government pays a job fee of Rs 800 per biogas plant constructedon turnkey basis with three years’ warranty for trouble-free functioningof the plant in north-eastern states, Sikkim, Jammu and Kashmir,Himachal Pradesh, Uttaranchal, hilly districts, and islands. In otherregions, it is Rs 700 per plant. Financial support limited to 50% of therate of central subsidy is also provided for repair and revival of family-

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type biogas plants, which are at least five years old and have developedstructural defects thereafter.

Programme Implementation and TrainingSupport

The programme is mainly implemented by the state governments, directlyor through their designated agencies. The Khadi and Village IndustriesCommission is also designated as a national implementing organization.For installation of biogas plants, the block or district office or stateheadquarters of the concerned nodal agency may be contacted.

Training is integral to the National Biogas Programme. Trainingprogrammes for construction, maintenance, and use of biogas plantsare regularly organized by the implementing agencies with central

National Biogas Programme: central subsidy for different categories andareas for setting up biogas plants

Category/Area Central subsidy per plant

North-eastern states and Sikkim Rs 11 700(except plain areas of Assam)

Plain areas of Assam Rs 9000

Jammu and Kashmir, Himachal Pradesh, Rs 4500 (restricted toUttaranchal (excluding Terai region), Nilgiris Rs 3500 for 1 m3 fixedof Tamil Nadu, Sadar Kurseong and dome type)Kalimpong sub-divisions of Darjeeling,Sunderbans, Andaman and Nicobar Islands

Scheduled Caste, Scheduled Tribe, desert Rs 3500 (restricted todistricts, small and marginal farmers, landless Rs 2800 for 1 m3 fixedlabourers, Terai region of Uttaranchal, dome type)Western Ghats and other notified hilly areas

All others Rs 2700 (restricted to Rs 2100for 1 m3 fixed dome type)

Table 4

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Table 5

Financial support for training courses

Training course/ Duration Number of trainees CFA* per courseTarget audience (days) per course (Rs)

Users 1 50–60 1000

Staff 2–3 10–15 5000

Refresher/construction-cum-maintenance 16 10 19000

Turnkey workers 21 days 10 38500

*central f inancial assistance

Biogas development and training centres

College of Technology and AgriculturalEngineering

Maharana Pratap University ofAgriculture and Technology

Udaipur – 313 001

Department of Bio-EnergyAgricultural Engineering College and

Research InstituteTamil Nadu Agricultural UniversityCoimbatore – 641 003

Department of Agricultural EngineeringHimachal Pradesh Krishi

VishvavidyalayaPalampur – 176 062

Chemical Engineering DepartmentIndian Institute of TechnologyKharagpur – 721 302

Department of AgriculturalEngineering

University of Agricultural SciencesGKVK, Bangalore – 560 065

Department of Civil EngineeringPunjab Agricultural UniversityLudhiana – 141 004

Centre of Energy Studies and ResearchDevi Ahilya VishwavidyalayaKhandwa Road, Indore – 452 017

Planning Research and Action DivisionState Planning InstituteUttar Pradesh, Kalakankar HouseLucknow – 226 024

College of Home ScienceGB Pant University of Agriculture and

Technology, Pantnagar – 263 145

Box 1

financial assistance. The quantum of central financial assistanceprovided for various training programmes is given in Table 5. Biogasdevelopment and training centres established in various parts of thecountry (Box 1) also provide technical training and publicity supportfor the programme.

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Some basic information

Cattle population in the country 289 million (Livestock census:1997)

Availability of cowdung 200 million tonnes

Availability of animal wastesCow 10 kg/dayCalf 5 kg/dayBuffalo 15 kg/dayPig 2 kg/dayGas production per kg of wet dung 0.04 m3/day

Biogas requirement for various applicationsFor cooking 0.3–0.4 m3 per day per personFor lighting 0.12 m3 per hour per 100 candle power lightFor electricity generation through 0.6 m3 per kWh

dual-fuel engineFor electricity generation through 0.75 m3 per kWh

100% biogas engine

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Rajiv Gandhi Akshay Urja Diwas

On 20 August 2004 – the 60th Birth Anniversary of our Late PrimeMinister Mr Rajiv Gandhi – the Ministry organized the Rajiv GandhiAkshay Urja Diwas. Initiated by the Hon’ble Minister of State (Non-Conventional EnergySources), Mr V Muttemwar,the occasion saw the releaseof a commemorative stampby the Hon’ble PrimeMinister, Dr ManmohanSingh, at a function attendedby Smt. Sonia Gandhi,Chairperson, UnitedProgressive Alliance (UPA),Members of the UnionCabinet, Members ofParliament, Chief Ministers,Foreign Dignitaries, Administrators, Scientists, and students amongothers.

The day was also appropriate to advocate renewable energy, sinceMr Rajiv Gandhi was a keen enthusiast of scientific advances that wouldenable India to leap into the 21st century. Thus, a human chain ofnearly 12 000 school children was formed in the National Capital topromote a renewable future. In the rest of the country too, functionssuch as rallies and human chains were organized. In addition,competitions such as essay writing, painting, quizzes, and debates wereheld, all of which covered different aspects of renewable energy – frombiogas to biomass to solar, hydro, and wind power. The essence ofthese public activities was to generate mass awareness and disseminateinformation about the advances made in renewable energy technologies,and with the ultimate objective of achieving ‘Akshay urja se desh vikas– Gaon gaon bijlee, ghar ghar prakash’. The success of the Rajiv GandhiAkshay Urja Diwas has encouraged the Ministry to make it an annualaffair, to be celebrated on 20 August every year.

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For more information, please contact

Ministry of Non-ConventionalEnergy Sources

Block No. 14, CGO ComplexLodi Road, New Delhi – 110 003

DisclaimerEvery effort has been made to provide correct information in this booklet. However, the Ministry ofNon-Conventional Energy Sources (MNES) does not assume any responsibility for the accuracyof the facts and figures mentioned here, nor for any consequences arising out of use of anyinformation contained in this publication.

Tel. +91 11 2436 0707+91 11 2436 0404

Fax +91 11 2436 1298

Shri Vilas MuttemwarMinister of State (Independent Charge)

Non-Conventional Energy Sources, Government of IndiaNew Delhi – 110 003

‘The promotion of renewable energy sources in the

country requires widespread publicity and greater

awareness of the potential of these energy sources

and the products available. The Ministry of Non-

Conventional Energy Sources is expanding several

of its programmes so that these sources can

contribute to sustainable development of the nation.

The Ministry will work towards reducing the costs

of renewable energy products and making them

easily available to the people. The motto of the

Ministry is “Akshay urja se desh vikas” and the

ultimate goal is “Gaon gaon bijli, ghar ghar prakash”.’

1 Biogas

Ministry of Non-Conventional Energy Sources, Government of IndiaBlock No. 14, CGO Complex, Lodi Road, New Delhi – 110 003

Web site: www.mnes.nic.in

Booklets in this Series

1 Biogas

2 Biomass

3 Solar Heat

4 Solar Electricity

5 Energy Recovery from Wastes

6 Wind Energy

7 Small Hydro Power

8 Hydrogen Energy

9 Solar Energy Centre

10 Centre for Wind Energy Technology

11 Indian Renewable Energy DevelopmentAgency Ltd

12 Information and Public Awareness