BPCL

Compressed Bio Gas or Bio-CNG

‘Bio-CNG’ is purified form of bio-Gas whose composition & energy potential is similar to that of fossil based natural gas and is produced from agricultural residues, animal dung, food waste, MSW and Sewage water. Bio-gas is produced through a process of anaerobic decomposition from waste / biomass sources like agriculture residue, cattle dung, sugarcane press mud, municipal solid waste, sewage treatment plant waste, etc. After purification, it is compressed and called Compressed Bio-Gas (CBG) which has more than 90 % methane content. Further, Compressed Bio-Gas has properties similar to the commercially available natural gas and can be used as an alternative, renewable automotive fuel.

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Benefits of Compressed Bio Gas

There are multiple benefits from converting agricultural residue, cattle dung and municipal solid waste into CBG on a commercial scale:

  • Responsible waste management, reduction in carbon emissions and pollution
  • Additional revenue source for farmers
  • Boost to entrepreneurship, rural economy and employment
  • Support to national commitments in achieving climate change goals Reduction in import of natural gas and crude oil
  • Buffer against crude oil/gas price fluctuations
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Technology Availability

Bio-gas is produced naturally through a process of anaerobic decomposition from waste/biomass sources like agriculture residue, cattle dung, sugarcane press mud, municipal solid waste, sewage treatment plant waste, etc.

The biogas produced contains approximately 55% to 60% methane, 40% to 45% carbon dioxide and trace amounts of hydrogen sulphide. Biogas is purified to remove carbon dioxide and hydrogen sulphide gases. After purification, it is compressed and called CBG, which has pure methane content of over 95%. The CBG can then be transported through cylinder cascades or pipelines to retail outlets.

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Sources for CBG production

The Government has recognized several sources of generating Biogas which can be further converted to CBG, some of which are poultry waste, agriculture waste, cattle dung, treatable industrial waste, waste from sugar industry, Municipal solid waste (MSW), waste from paper mills, dairies waste, etc.

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CBG from Agricultural Waste

As the second largest producer of agricultural product, Indian agricultural sector constitutes to around 15.4% of its GDP and accounts for about 7.39% of total global agricultural output in 2017. Thus generating about 350 million tonnes of agricultural waste every year as per researchers at IIT-B and the Ministry of New and Renewable.

Energy estimates this waste can generate more than 18,000 MW of power every year, apart from generating green fertilizer for farms. If the farmers do not find buyers for the waste they either burn it which releases huge amount of emissions, or dump it leading to soil and water contamination because of high residue of toxic chemicals. These wastes can be utilized effectively to produce fuels like ethanol and biogas.

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CBG from Municipal Waste

MSW majorly includes commercial and residential wastes generated in a municipal or notified areas, excluding industrial hazardous wastes but including treated bio-medical wastes.

As per the report of planning commission (2014), 377 million people residing in urban area generate 62 million tons of MSW per annum currently and it is projected that by 2031 these urban canters will generate 165 million tons of waste annually and by 2050 it could reach 436 million tons.

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CBG from waste from Sugar Industry

Sugar industry is the second largest agro based industry in India and contributes significantly for the socioeconomic development of the rural population. Indian sugar industry plays a major role in global sugar market, being the world’s second largest producer of sugar after Brazil, producing 15%-20% of the total sugar production worldwide. These industries also produce considerable amount of waste and by-products.

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Waste products generated during various phases of sugar production as follows

Spent Wash: Fermentation of molasses and the subsequent distillation gives rise to 12-14 litres of effluent per litre of ethanol manufactured mainly in the form of spent wash. Incineration type of distilleries uses the spent wash as the fuel where the entire spent wash along with some fuel is burnt so as to keep the distilleries running. Such distilleries can be found to be running throughout the year and none of the spent wash is wasted. Spent wash is also used in production of compost manure which is then used in farms as fertilizers. Sugar factories also generate substantial amount of money from this business. Some factories have a biogas plant. Portion of spent wash is also used to produce biogas.

Press mud: It is the residue of the filtration of the sugarcane juice. Generally, on an average, the amount of press mud produced is 3.5%-4% of the sugarcane crushed. As of the now the there is no means of converting this press mud into usable CBG in this factory. Press mud is mainly used to manufacture compost manure which is then commercially sold for agricultural purposes. Also technology to produce biogas from press mud is not available in India. But recently some German companies have shown their interests to come to India with this technology.

Bagasse: It is the remains of the sugar cane after extracting the sugar juice from sugar cane. This bagasse at present mainly serves two purposes- For thermal electricity production from co-generation plant. For running the boilers of sugar industry. This bagasse can be used for production of bio-gas.

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Promotional schemes

  • RBI has announced CBG funding under “Priority Sector Lending” under Renewable Energy.
  • MNRE has notified Central Financial Assistance (CFA) of Rs. 4 Cr. per 4800 Kg of CBG per day generated with max. of Rs. 10 Cr. per project.
  • For exclusive financing of CBG plants, SBI has developed a new Loan Product titled “Compressed Bio Gas (CBG) under SATAT recently in the month of October, 2020.
  • Bank of Baroda has developed a new Loan Product titled “Bank of Baroda Scheme for Financing Compressed Bio Gas Plants under SATAT and the proposal received on 22/12/2020.
  • Inclusion of Digester BioGas Slurry DBGS under Fertilizer Control Order 1985 has been approved by the Minister of Agriculture vide Gazette notification dated 13/07/2020.
  • MoP&NG is in discussion with Global Financial Institutions like ADB, World Bank, JICA, KfW, etc. for financing of CBG Plants
  • CPCB vide letter dated 30/04/2020 directed to inclusion of CBG under ‘White Category’. Pollution Control Boards of Delhi, Gujarat and Uttar Pradesh, Madhya Pradesh, Punjab 7 West Bengal have already classified Bio-gas plants under "White category".