What is CBG (Compressed Biogas)?
Compressed Biogas (CBG), also called Bio-CNG, is purified and compressed biogas containing >95% methane at 200-250 bar pressure. It is chemically identical to fossil-based CNG but produced from organic waste like cattle dung, agricultural residues, food waste, and municipal solid waste. CBG can directly replace CNG in vehicles without any engine modification, making it a drop-in renewable fuel.
India's SATAT (Sustainable Alternative Towards Affordable Transportation) scheme aims to produce 15 MMT CBG by 2030, creating a nationwide network of 5,000+ CBG plants. OMCs (IOCL, BPCL, HPCL) commit to purchase CBG at ₹46-50 per Kg under 10-year off-take agreements, ensuring guaranteed revenue for plant operators.
CBG vs. Biogas vs. CNG
| Parameter |
Biogas (Raw) |
CBG / Bio-CNG |
CNG (Fossil) |
| Methane Content |
55-70% |
>95% |
92-98% |
| CO₂ Content |
30-45% |
<2% |
<2% |
| H₂S |
500-3000 ppm |
<5 ppm |
0 |
| Pressure |
50-150 mbar |
200-250 bar |
200-250 bar |
| Energy Density |
21-24 MJ/m³ |
36-38 MJ/m³ |
36-38 MJ/m³ |
| Applications |
Cooking, gensets (on-site) |
Vehicle fuel, grid injection |
Vehicle fuel |
Perfect Biogas CBG Plant Range
| CBG Capacity |
Raw Biogas Input |
Feedstock Requirement |
Vehicle Equivalent |
Project Cost |
| 500 Kg/day |
1,000 m³/day |
25-30 Tons/day (cattle dung/poultry/food waste) |
200 cars/day |
₹8-10 Crores |
| 1 Ton/day |
2,000 m³/day |
50-60 Tons/day |
400 cars/day |
₹14-18 Crores |
| 3 Tons/day |
6,000 m³/day |
150-180 Tons/day |
1,200 cars/day |
₹35-45 Crores |
| 5 Tons/day |
10,000 m³/day |
250-300 Tons/day |
2,000 cars/day |
₹55-70 Crores |
| 10 Tons/day |
20,000 m³/day |
500-600 Tons/day |
4,000 cars/day |
₹100-130 Crores |
Note: Project costs are indicative after 30-40% subsidies under SATAT. Actual cost depends on feedstock type, location, land cost.
CBG Plant Process Flow
A typical CBG plant has four main stages:
Stage 1: Feedstock Pre-processing
- Purpose: Reduce particle size, remove inorganics, adjust moisture
- Equipment: Shredders, magnetic separators, density separators, pulpers
- Output: Homogeneous slurry with 8-12% Total Solids (TS)
- MSW Specific: Segregate plastics, metals, sand (60-70% of MSW is non-biodegradable)
- Critical: Poor pre-processing reduces biogas yield by 30-50%
Stage 2: Anaerobic Digestion
- Reactor Type: CSTR (Continuously Stirred Tank Reactor), UASB (Up-flow Anaerobic Sludge Blanket), or Plug Flow
- Capacity: 2,000-20,000 m³ digester volume (HRT 20-40 days for MSW, 15-25 days for cattle/poultry)
- Temperature: Mesophilic 35-38°C (heating coils maintain temperature in winter)
- pH Control: 6.8-7.2 optimal (add lime if acidic, CO₂ purging if alkaline)
- Output: Raw biogas 55-65% CH₄, 30-40% CO₂, 500-2000 ppm H₂S
Stage 3: Biogas Upgradation (Purification)
Remove CO₂, H₂S, moisture, siloxanes to achieve >95% methane:
H₂S Removal (De-sulfurization):
- Method 1 - Biological: Air injection (2-6% of biogas volume) in digester to convert H₂S to elemental sulfur by sulfur-oxidizing bacteria. Low cost (₹10-15 Lakhs), but only reduces to 50-100 ppm.
- Method 2 - Iron Sponge: Fe₂O₃ reacts with H₂S to form FeS. Capacity: 1kg Fe₂O₃ removes 0.8kg H₂S. Replacement every 6-12 months (₹50,000-2 Lakhs/year). Achieves <5 ppm.
- Method 3 - Activated Carbon: Impregnated with KOH/NaOH. Best for low H₂S (<200 ppm), high efficiency >99%. Cost: ₹30-50 Lakhs for 1 Ton/day plant.
CO₂ Removal (Methane Enrichment):
- a) Water Scrubbing (Most Common): Biogas passes through pressurized water tower (8-10 bar). CO₂ dissolves 25x better than CH₄. Efficiency: 95-98% methane purity, 98% recovery. Operating cost: ₹2-3 per Kg CBG. Capex: ₹4-5 Crores for 1 Ton/day.
- b) Pressure Swing Adsorption (PSA): Activated carbon/zeolite adsorbs CO₂ under pressure (4-8 bar), desorbs under vacuum. Efficiency: 96-98% purity, 92-95% recovery. Lower OPEX than water scrubbing (no water/chemical consumption), but higher capex (₹6-8 Crores for 1 Ton/day).
- c) Membrane Separation: Selective polymer membranes allow CO₂ to permeate faster. Compact footprint, but 15-20% methane slip reduces recovery to 85-90%. Used in small plants (<500 Kg/day).
- d) Chemical Scrubbing (Amine/Selexol): MEA (Monoethanolamine) absorbs CO₂, regenerated by heating. Highest purity (>99%), but high energy (thermal regeneration) and OPEX. Rare in India, common in Europe.
Stage 4: Compression & Storage
- Compressor: Multi-stage reciprocating or screw compressor (4-5 stages) compresses CBG from 1 bar (upgradation outlet) to 200-250 bar
- Capacity: 100-500 Nm³/hr per compressor (1 compressor for 500 Kg/day plant, 3-4 compressors for 5 Ton/day plant)
- Inter-cooling: After each stage to prevent overheating, remove moisture
- Storage: Cascade of CNG cylinders (200-250 bar) with 4-8 hours buffer capacity
- Dispensing: Standard CNG dispenser with flow meter, automatic cut-off at full cylinder
- Power Consumption: 0.15-0.20 kWh per Kg CBG compressed (₹1.2-1.6/Kg at ₹8/kWh)
Feedstock Options & Yield
| Feedstock Type |
Biogas Yield (m³/Ton) |
CBG Yield (Kg/Ton) |
Best Digester Type |
| Cattle Dung (fresh) |
35-45 |
17-22 |
CSTR, Fixed Dome |
| Poultry Litter |
60-80 |
30-40 |
CSTR (with pre-acidification) |
| Food Waste (restaurant/hotel) |
80-120 |
40-60 |
CSTR, Two-stage |
| Agricultural Residues (wheat straw) |
150-200 |
75-100 |
Dry AD, Plug Flow |
| MSW (organic fraction 40-50%) |
50-80 |
25-40 |
UASB, Dry AD |
| Distillery Spent Wash |
20-30 |
10-15 |
UASB (high COD 80,000-120,000 mg/L) |
| Press Mud (sugar industry) |
50-70 |
25-35 |
CSTR |
Project Economics - 1 Ton/day CBG Plant Example
Capital Expenditure (CAPEX)
- Feedstock Pre-processing: Shredder, separator, conveyor - ₹1.5 Crores
- Anaerobic Digester: 3,500 m³ CSTR with heating, agitation - ₹5 Crores
- Biogas Upgradation: H₂S scrubber + Water scrubbing tower - ₹4.5 Crores
- Compression & Storage: 2 × 100 Nm³/hr compressors, cascade - ₹3 Crores
- Civil & Utilities: Buildings, roads, water, power - ₹2 Crores
- Instrumentation & Control: SCADA, sensors, automation - ₹1 Crore
- Total CAPEX: ₹17 Crores
- Subsidy (30-40%): -₹5-7 Crores (MNRE, state schemes)
- Net Investment: ₹10-12 Crores
Operating Expenditure (OPEX) per Year
- Feedstock Procurement: 60 Tons/day × ₹500/Ton × 330 days = ₹1 Crore (may be free if waste disposal avoidance)
- Electricity (parasitic load): 150 kW × 20 hrs × ₹8/kWh × 330 days = ₹80 Lakhs
- Water (scrubbing system): 5 m³/hr × 20 hrs × ₹20/m³ × 330 days = ₹7 Lakhs
- Manpower: 1 manager + 2 operators + 4 workers = ₹30 Lakhs/year
- Maintenance (spares, repairs): 3-4% of CAPEX = ₹50-70 Lakhs
- Total OPEX: ₹2.7-3 Crores/year
Revenue Streams
- CBG Sales to OMCs: 1 Ton/day × 330 days × ₹48/Kg = ₹1.58 Crores/year
- Gate Fees (waste disposal charges): 60 Tons/day × ₹500/Ton × 330 days = ₹1 Crore/year (if MSW/industrial waste)
- Carbon Credits: 800 Tons CO₂e avoided × ₹500/Ton = ₹4 Lakhs/year
- Bio-slurry (organic manure): 40 Tons/day × ₹1,000/Ton × 330 days = ₹1.3 Crores/year
- Total Revenue: ₹4-4.5 Crores/year
Financial Viability
- Net Annual Profit: ₹4.2 Cr revenue - ₹2.8 Cr OPEX = ₹1.4 Crores
- Payback Period: ₹11 Cr net investment / ₹1.4 Cr profit = 7.8 years
- Internal Rate of Return (IRR): 12-15%
- Plant Life: 20-25 years (depreciation)
- Debt Option: 70% bank loan at 9% for 10 years improves equity IRR to 18-22%
SATAT Scheme - Government Support
Launched in 2018 by Ministry of Petroleum & Natural Gas, SATAT (Sustainable Alternative Towards Affordable Transportation) provides:
- Guaranteed Off-take: 10-year CBG purchase agreement with OMCs at ₹46-50/Kg (linked to diesel/CNG prices)
- Capital Subsidy: 30-40% of project cost under MNRE, NABARD, state schemes (max ₹10-15 Crores)
- Priority Sector Lending: Banks provide 9-10% interest loans (vs. 12-13% commercial)
- Single-Window Clearance: Simplified approvals for environment, pollution, fire NOC
- 100% FDI Allowed: Automatic route for foreign investment
- Network Access: OMCs provide cascade connection to existing CNG stations or procure at plant gate
Expression of Interest (EOI): Submit to IOCL/BPCL/HPCL with feedstock details, location, proposed capacity. We assist with complete application.
Approvals & Compliance
CBG plants require 10-15 statutory approvals (6-12 months timeline):
- Environment Clearance: State PCB (if <3 Tons/day) or MoEF (if >3 Tons/day)
- CNG Cascade License: PESO (Petroleum & Explosives Safety Organization) for gas storage/compression
- BIS Certification: IS 16087:2016 for CNG quality (methane >92%, H₂S <10 mg/m³)
- Fire NOC: State fire department for flammable gas handling
- Electricity Connection: 11 kV HT connection (150-300 kW load)
- Water NOC: Groundwater authority for borewell (if scrubbing)
- Building Approval: Local municipal corporation for civil construction
- CPCB Authorization: Waste processing under SWM Rules 2016 (if MSW feedstock)
Our Service: We prepare all documents, liaise with departments, ensure 100% approvals within 8-10 months (vs. 18-24 months if self-managed).
Perfect Biogas CBG Advantage
- Proven Track Record: 5 operational CBG plants (500 Kg to 3 Ton/day capacity) across India
- Technology Tie-ups: Collaboration with European leaders (DMT, Malmberg) for upgradation systems
- In-house R&D: Pilot plant in Faridabad for feedstock testing, process optimization
- Feedstock Flexibility: Our plants handle 5-6 co-substrates simultaneously (vs. single-feedstock designs)
- Performance Guarantee: 95% uptime, guaranteed methane purity >93% (vs. typical 90%)
- SATAT EOI Support: 100% success rate in OMC approvals, PPA negotiation
- Turnkey EPC: Land survey → design → approvals → construction → commissioning → O&M training - single vendor
- Financing Assistance: Connect with NABARD, PFC, REC for 70% project finance
Case Study - 1 Ton/day CBG Plant, Maharashtra
Client: Municipal Corporation (3 lakh population)
Feedstock: 80 Tons/day segregated MSW (40% organic content = 32 Tons biodegradable)
Capacity: 1 Ton/day CBG (2,000 m³/day raw biogas)
Technology: Wet AD (CSTR) + Water Scrubbing + 2 × 100 Nm³/hr compressors
Project Cost: ₹17 Crores (₹5 Cr subsidy from MNRE, ₹12 Cr net)
Commissioning: April 2023
Performance (first year):
- Actual CBG production: 310 Tons (94% of design capacity)
- CBG sold to IOCL at ₹48/Kg: ₹1.49 Crores
- Gate fees (₹400/Ton MSW): ₹1.05 Crores
- Bio-slurry sales: ₹95 Lakhs
- Total revenue: ₹3.5 Crores
- OPEX: ₹2.2 Crores (lower than estimate as MSW feedstock is free + waste disposal avoided)
- Net profit: ₹1.3 Crores (11% return on net investment)
Impact:
- Diverted 26,000 Tons/year MSW from landfill (extended landfill life by 3-4 years)
- Avoided 2,400 Tons CO₂e emissions (equivalent to planting 60,000 trees)
- Fueled 150 municipal buses with CBG (replacing diesel)
- Created 25 direct jobs (plant operation + waste collection)
Get Started with Your CBG Project
We provide free preliminary feasibility assessment including:
- Feedstock availability survey (5 km radius from plant site)
- Biogas yield estimation based on feedstock composition
- Preliminary plant layout, capacity recommendation
- CAPEX/OPEX estimate with ROI projections
- Subsidy scheme eligibility check
Contact CBG Division:
- 📞 Phone: +91-9310440810 (CBG Project Manager)
- ✉️ Email: cbg@perfectbiogas.com
- 📍 Office: B-301, Okhla Industrial Area Phase I, New Delhi 110020
- 📋 Request DPR: Email feedstock details (type, quantity/day, location)
← Back to Homepage