All About Compressed Biogas
The Future of Green Fuel in India and Why Membranes Are Leading the Way
As the world races toward sustainable energy alternatives, Compressed Biogas (CBG) stands out as a practical, scalable, and eco-friendly fuel source. India, an agrarian economy with vast biomass resources, is uniquely positioned to lead this transition. With government-backed schemes like SATAT and the support of MNRE, the CBG sector is witnessing rapid growth.
But to unlock CBG’s full potential, raw biogas must undergo purification or upgrading. This is where membrane technology is making a big impact—offering a cleaner, more energy-efficient, and cost-effective solution compared to conventional technologies.
This blog explores the world of CBG—its generation, upgrading, applications, and why membrane systems are emerging as the top choice for modern CBG plants.
🔍 What is CBG and Why Does It Matter?
Compressed Biogas (CBG) is a purified and compressed form of biogas containing 90–98% methane (CH₄). It is chemically equivalent to Compressed Natural Gas (CNG) and can be used for:
Fuel for vehicles (cars, buses, tractors, trucks)
Powering gas engines for electricity generation
Cooking in commercial kitchens
Injection into natural gas pipelines
CBG is derived from raw biogas, which is generated through anaerobic digestion of organic waste. This waste can include:
Cow dung and poultry litter
Agricultural residues
Food and kitchen waste
Municipal solid waste
Sewage sludge and industrial effluents
Typical raw biogas composition:
Methane (CH₄): 50–70%
Carbon Dioxide (CO₂): 30–50%
Hydrogen Sulfide (H₂S), Water Vapor, Ammonia, etc.
Biogas Upgrading Value Chain
🛢️ Why Upgrading is Essential?
Raw biogas in its natural form cannot be directly used as a transport fuel or injected into pipelines. It must be upgraded to remove:
CO₂ – Reduces calorific value and increases corrosion
H₂S – Highly corrosive and toxic
Water Vapor – Causes condensation and equipment damage
To qualify as CBG (Compressed Biogas), the methane concentration must reach ≥90% as per Bureau of Indian Standards (BIS). Upgrading increases energy content, improves gas purity, and ensures safety and compliance with grid/fuel standards.
🇮🇳 Government Push – SATAT and MNRE
India’s commitment to clean mobility and waste-to-energy is reflected in flagship policies:
SATAT – Sustainable Alternative Towards Affordable Transportation
Launched by the Ministry of Petroleum and Natural Gas, SATAT aims to:
Set up 5,000 CBG plants by 2025
Generate 15 million tonnes of CBG per year
Procure CBG via Oil Marketing Companies (OMCs) like IOCL, BPCL, HPCL
Create employment and rural entrepreneurship
MNRE – Ministry of New and Renewable Energy
MNRE supports the biogas sector through:
Capital subsidies for biogas and upgrading plants
Technical guidelines for project execution
Policy support for off-grid energy and bio-CNG bottling
Together, SATAT and MNRE are creating a robust ecosystem for CBG adoption—from waste collection and digestion to purification, compression, and fuel distribution.
⚙️ CBG Upgrading Technologies: A Comparative Overview
There are multiple biogas upgrading techniques, each with its pros and cons:
1. Amine Scrubbing
Chemical method using amines to absorb CO₂.
Requires high-temperature regeneration.
Suitable for large-scale projects but complex.
Pros: High CH₄ purity (>99%)
Cons: High energy use, chemical degradation, not modular
2. Water Scrubbing
Uses pressurized water to absorb CO₂ and H₂S.
Common in older setups.
Pros: No chemicals
Cons: High water consumption, methane loss (2–5%)
3. PSA / VPSA (Pressure Swing Adsorption)
Adsorbent materials (e.g., zeolites) used under pressure.
Gas is separated based on adsorption capacity.
Pros: Dry process, no water/chemicals
Cons: High methane loss (up to 10%), complex valve systems
4. Membrane Separation (The Modern Solution)
Uses polymer membranes to separate CO₂ based on permeability.
Modular, scalable, and energy-efficient.
Pros: Low OPEX, <2% CH₄ loss, compact, low environmental impact
Cons: Requires pre-filtration for long membrane life
🧬 How Membrane Technology Works?
Membranes work on the principle of selective gas permeation. Gases like CO₂, H₂S, and water vapor permeate through the membrane faster than methane.
Multi-stage Membrane Process:
Stage 1: Bulk CO₂ removed; methane-rich gas retained
Stage 2: Polishing step to further purify CH₄
Stage 3: Optional final stage for >96% CH₄
The result is high-purity methane on one side and CO₂-rich off-gas on the other—without using chemicals or generating wastewater.
✅ Benefits of Membrane-Based Upgrading
Membranes are fast becoming the go-to choice for modern CBG plants due to:
🔹 Energy Efficiency
Operates at moderate pressures (7–15 bar)
No need for heat or regeneration cycles
🔹 Compact and Modular
Skid-mounted systems
Quick installation and commissioning
🔹 Environmentally Friendly
No liquid discharge
No toxic chemical waste
🔹 Low Methane Slip
Less than 2% with proper multi-stage design
🔹 Scalable for Any Size
Suitable for 200 Nm³/day to 5,000+ Nm³/day plants
🔹 Low Maintenance
Minimal moving parts
No need for chemical replenishment or wastewater handling
🔬 Innovation in Membrane Materials – Airrane’s Edge
South Korea-based Airrane is at the forefront of hollow fiber membrane innovation. Their membranes offer:
High selectivity for methane
Long life span (10,000+ hours)
Resistance to fouling and moisture
High throughput with low footprint
Daltech Engineering Pvt. Ltd. proudly partners with Airrane to offer SATAT and MNRE compliant membrane in India—backed by reliable service, design support, and local inventory.
🌍 Real-World Applications of CBG
🚜 Agriculture
Power tractors and irrigation pumps
Reduce diesel dependency
Convert animal waste to fuel + fertilizer
🏙️ Municipal Corporations
Convert sewage sludge and food waste into CBG
Fuel city buses or garbage trucks
🏭 Industries & Hotels
Replace LPG in kitchens
Generate on-site power
🚚 Logistics & Fleets
Fuel for commercial vehicles
Lower fuel cost per km, lower emissions
CBG enables energy circularity, turning waste into wealth and reducing dependence on imported fossil fuels.
🔋 Environmental and Economic Impact
By switching to CBG and membrane-based upgrading:
CO₂ emissions drop significantly
Import bills are reduced
Jobs are created in waste collection, plant operation, and logistics
Decentralized energy infrastructure strengthens rural areas
Membrane systems also enable lower energy consumption per unit of upgraded gas, ensuring both economic and ecological returns.
🌟 India and the World: Shared Progress
Countries like Germany, Sweden, the U.S., and South Korea are leveraging membranes for biogas upgrading. In India, the momentum is building—with Airrane membrane.
Global confidence, local adaptation, and policy alignment make membranes the future-proof choice for India's CBG revolution.
✅ Final Thoughts: Clean Energy Starts with Clean Technology
The future of energy is renewable, decentralized, and circular. CBG, with its ability to convert waste into usable fuel, represents this future in action.
Choosing the right upgrading technology is key—and membranes offer unmatched advantages:
High efficiency
Low operating cost
Minimal environmental impact
Scalability for every project size
Whether you’re a municipal body, farmer, EPC contractor, or entrepreneur—membrane systems empower your biogas journey with simplicity and sustainability.
💬 Need a Reliable CBG Upgrading Solution?
At Daltech Engineering, we deliver Airrane membrane systems designed for Indian conditions, backed by expert support.
📞 Call us: 85880 48800
📧 Email: sales@daltech.in
🌐 Visit: www.daltech.in
🔗 Explore Our Membrane Solutions