Compressed Biogas (CBG)
Why in News?
- Compressed Biogas (CBG) is in the news because the Union Cabinet approved a landmark national unified scheme under the GOBARdhan initiative.
- This massive policy overhaul will be implemented from FY 2026-27 to FY 2035-36 to transform India’s clean energy matrix, scale up domestic CBG production ten-fold, and mobilize large-scale private investments.
About Compressed Biogas (CBG)
- The Composition: It is a purified, high-pressure form of biogas comprised of more than 90% methane, making it chemically identical to commercial Compressed Natural Gas (CNG).
- The Process: Produced via anaerobic digestion—the biological breakdown of organic matter by specialized bacteria in a sealed environment completely devoid of oxygen.
- Four-Stage Chemical Reaction: The transformation occurs through four precise microbial steps: Hydrolysis, Acidogenesis, Acetogenesis, and finally Methanogenesis.
- Purification Phase: Raw biogas undergoes severe desulfurization, decarbonization, and dehydration to strip out toxic Hydrogen Sulfide (Hâ‚‚S), Carbon Dioxide (COâ‚‚), and water vapor.
- Final Compression: The highly purified biomethane gas is compressed to a high pressure of 250 bars for seamless commercial distribution.
Key Raw Materials (Feedstocks) Used
- Agricultural Residue: Crop waste including paddy straw, wheat straw, cotton stalks, and maize.
- Industrial Agro-Waste: Press mud and bagasse extracted from sugar mills, along with distillery liquid effluents.
- Animal Waste: Cattle dung, poultry litter, and dairy farm organic slurries.
- Municipal Solid Waste (MSW): The biodegradable organic fraction of urban waste segregated directly at the source.
- Sewage Treatment: Sewage plant sludge and organic marine biomass like seaweed sludge.
Benefits & Significance
- Import Substitution: Directly scales down India's multi-billion-dollar reliance on Liquefied Natural Gas (LNG) and Crude Oil imports.
- Target 2030 Support: Bolsters India's state goal to elevate natural gas to a 15% share of the national energy mix by 2030 (up from roughly 6%).
- Net Zero 2070: Mitigates open field crop-residue burning (paddy straw burning) and curbs powerful fugitive methane emissions from landfills.
- Circular Bioeconomy Wealth: Generates Bio-slurry, a premium organic non-chemical fertilizer and soil conditioner that reduces chemical fertilizer subsidies.
- Rural Micro-Entrepreneurship: Provides farmers and village cooperatives with secondary income streams from waste aggregation.
Present Implementation Challenges
- High Capital Costs: Initial setup is heavily machine-intensive, with plant equipment and machinery accounting for up to 80-90% of total project CAPEX.
- Feedstock Pricing & Quality: Seasonal volatility and lack of fixed regulatory pricing agreements cause plant operations to fall below optimal capacity.
- Pipeline Infrastructure Gaps: A majority of operating plants lack physical proximity to City Gas Distribution (CGD) networks, restricting physical product distribution.
- Byproduct Waste: Processing systems struggle to commercially isolate and monetize the huge volumes of COâ‚‚ stripped during purification.
- Financing Hurdles: Commercial banks often show hesitation, demanding heavy collateral and applying high borrowing interest rates starting at 11.5%.
Recent Footprint of CBG in India
| Parameter | Current Status & Trajectory |
| Operational Plants | 126+ active plants commissioned nationwide |
| Current Production | Over 860 tons of clean gas generated daily |
| Plants Under Construction | 82+ actively building (Uttar Pradesh leading with 80) |
| Network Expansion | ₹994 crore dedicated to directly piping CBG plants into city gas grids |
| Ultimate Roadmap Target | Set to scale up to 5,000 plants across India |
