by Biogas is a renewable source of energy generated from organic waste such as animal dung, agricultural residue, municipal solid waste, sewage, green waste and food waste through a natural process called anaerobic digestion. India has enormous potential to generate biogas from its huge livestock population and agricultural residue. Biogas can help tackle two major issues faced by our country – management of agricultural and animal waste and lack of access to clean cooking fuel in rural areas.
What is Biogas?
Biogas is a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. The main constituents of biogas are methane (CH4) which ranges between 50-70% and carbon dioxide (CO2) which ranges between 30-50%. Biogas also contains small amounts of other gases like hydrogen sulfide.
The process of anaerobic digestion takes place in a closed chamber called digester, where biodegradable material like cow dung or food waste is fed. Several types of anaerobic bacteria and other microorganisms act upon the biomass in the absence of oxygen and break down the organic matter. In the process, the bacteria produce biogas as a byproduct which is trapped inside the digester.
Applications of Biogas
The main use of biogas is for cooking purposes in rural households. Biogas burns similar to Liquefied Petroleum Gas (LPG) and can be used for cooking and lighting. It provides a clean source of fuel and prevents indoor air pollution.
Some other applications of biogas include:
– Generation of Electricity: Biogas can be used to run generators and produce electricity especially for decentralized off-grid applications. The slurry left after biogas production also makes for a good fertilizer.
– Automotive fuel: Upgraded biogas known as bio-CNG (compressed natural gas) can be used as an automotive fuel. Several cities in India are running public transport buses on bio-CNG.
– Process Heat: Biogas provides an excellent source of heat energy which can be used for industrial processes like drying, steam generation etc. Industries like food processing can meet significant part of their thermal energy needs through biogas.
– Piped Natural Gas: After proper treatments and upgrades, biogas can be injected into the natural gas grid and distribution system for wider applications. Countries like Germany and Sweden do it on a large scale.
Benefits of Biogas
Environment-friendly:
– Biogas is a renewable source of energy generated from organic waste materials thus preventing their methane emissions into the atmosphere.
– Prevents deforestation by reducing dependence on firewood for cooking.
– The slurry leftover after biogas production acts as an organic fertilizer for farms thus optimizing usage of resources.
Economical:
– Biogas systems helps farmers/communities gain energy self-sufficiency and reduce electricity/fuel bills.
– Can supplement or replace usage of subsidized LPG and help government save costly fuel subsidies.
– Decentralized small-scale plants are set up with low capital investment and have good operational cost recovery.
Health Benefits:
– Cooking with biogas eliminates smoke and reduces indoor air pollution especially in rural households where women do majority of cooking. This prevents many respiratory diseases.
– Biogas slurry when used as manure reduces use of chemical fertilizers and protects soil and underground water from pollution.
Employment Generation:
– Biogas sector helps create green jobs in areas of plant installation, operation & maintenance and technical support services across rural regions.
Issues and Challenges
While biogas is a very promising renewable option, its widespread diffusion in India still faces some hurdles:
– Lack of adequate financing mechanisms for setting up biogas plants beyond subsidy schemes. Capital cost remains a barrier for small and marginal farmers.
– Collection and transportation of biomass remains a logistical challenge, especially in dispersed rural settings.
– Absence of markets linked to value addition from biogas byproducts like biomanure limits economic incentive for operators.
– Limited technical know-how among rural population regarding construction and maintenance of biogas plants leads to low plant viability.
– Absence of supportive policies and regulations for activities like biogas grid injection and use of upgraded biogas in transport sector.
Government Initiatives
The Government of India has taken several steps to promote wider adoption of biogas through different ongoing programs:
– National Biogas and Manure Management Programme (NBMMP): Includes subsidizing family type biogas plants and community gas plants. Target is setting up 4 lakh plants per year.
– Sustainable Alternative Towards Affordable Transportation (SATAT) Initiative: Aims to set up 5,000 compressed biogas plants with targeted production of 15 MMT of bio-CNG by 2023.
– Swachh Bharat Mission: Supports biogas generation from municipal solid waste and targets construction of 75,000 biogas plants at waste processing sites.
– Schemes like Pradhan Mantri Ujjwala Yojana promoting LPG also encourages setting up biogas units as alternative cooking fuel in villages.
– Some states provide additional incentives like interest subvention, transportation subsidy for biomass etc. to boost localized projects.
With suitable policy push and implementation of integrated waste management programmes, biogas can emerge as one of the primary renewable sources of energy in India. It has enormous untapped potential to generate green fuel from agro and urban waste streams. Growing population also ensures uninterrupted feedstock availability if collection mechanisms are strengthened. If promoted on mission mode, biogas holds the promise to light up millions of households while helping country transition to more sustainable development.
