From raw biogas to vehicle-grade Bio-CNG
Raw biogas from a digester typically contains methane and a large share of carbon dioxide, plus hydrogen sulphide and moisture. To sell it as Bio-CNG, the gas must be cleaned, upgraded to a high methane content, monitored for quality and compressed. Biovardhan engineers this whole chain to integrate with the digestion system upstream, because purifier performance depends on stable gas flow and composition from the digesters.
- Raw biogas
- Gas holder
- H₂S removal
- Moisture removal
- CO₂ separation
- Quality analyser
- Compressor
- Bio-CNG cascade
What's included in a Biovardhan Bio-CNG plant
Feedstock & pretreatment
Receiving, storage, shredding, shearing and slurry preparation sized to your feedstock mix.
Anaerobic digestion
CSTR digesters with in-house agitators, heating and process control for stable biology.
Gas storage
AMOCO membrane gas holders, as Authorized Channel Partner for India.
Purification & upgrading
H₂S and moisture removal and CO₂ separation by water scrubbing, PSA or membrane, chosen per project.
Compression & dispensing
High-pressure compressors, cascades and integration for OMC outlets, cylinder transport or pipeline.
Automation & safety
PLC/SCADA, online CH₄/CO₂/H₂S monitoring, gas detection, fire protection and flare.
Bio-CNG gas quality: IS 16087:2025
Bio-CNG sold to oil marketing companies and CGD networks must meet the Bureau of Indian Standards specification IS 16087:2025 (Biogas – Biomethane – Specification) for biomethane / compressed biogas. In practice the plant must deliver:
- High methane content. Commercial plants typically target 95% and above.
- Very low CO₂, oxygen and nitrogen, which protects calorific value.
- Near-zero sulphur / H₂S, which protects engines, compressors and cylinders.
- Very low moisture (deep dew point), so no condensation in 250-bar storage.
We design upgrading, drying and polishing to the specification required by your offtaker. Quality is verified with online analysers and gas-chromatograph testing, with third-party lab reports for buyers.
Compression, cascades & dispensing
- Dry Bio-CNG
- LP / HP compressors
- Odorisation
- Cascade filling (≈250 bar)
- Truck-mounted cascades
- OMC outlet / industry
- Compressors: reciprocating LP and HP stages with variable-speed drives, ideally with a standby unit so one failure does not stop sales.
- Odorisation: mercaptan dosing so leaks can be smelled, as required for fuel gas.
- Cascades: banks of high-pressure cylinders for storage at the plant and for road transport to fuel stations. Plan the number of cascades and vehicles around daily output and travel distance.
- PESO licensing: compressed gas storage, filling and dispensing require approvals from the Petroleum and Explosives Safety Organisation. The layout, safety distances and fire protection are designed for it from day one.
How many cascades does a CBG plant need?
A typical truck-mounted cascade of about 40 cylinders (≈ 4,500 litres water capacity) carries roughly 700–800 kg of CBG at 250 bar. So:
| Plant capacity | Cascade loads per day | Planning note |
|---|---|---|
| 3 TPD | ≈ 4 | One or two trucks if the outlet is close |
| 5 TPD | ≈ 7 | Fewer cascades are needed if each truck makes two round trips a day |
| 10 TPD | ≈ 13–14 | Consider pipeline injection if a CGD network is nearby |
Keep enough cascades at site to store at least a day's production. That way, a delayed truck doesn't force the plant to flare gas.
Selling Bio-CNG to oil companies & CGD networks
Offtake agreements with oil marketing companies and city gas distributors put clear technical obligations on the producer. Plan for them in the plant design, not after commissioning:
- Quality monitoring: gas chromatograph or online analyser, sulphur analyser and moisture (dew point) analyser at the delivery point
- Custody-transfer metering, with calorific value and density determined to ISO 6976 and instruments calibrated by an ISO/IEC 17025-accredited lab
- Odorisation and pressure control, plus online data sharing of quantity and quality with the buyer
- Joint measurement records: buyer and seller periodically sign off quantities and quality
- Off-spec risk: gas that fails the specification can be rejected and not paid for, so upgrading reliability is directly revenue
- Pipeline injection needs a tie-in permission and NOC from the CGD entity. Cascade supply to retail outlets needs PESO approvals.
Bio-CNG plant capacities
- Bio-CNG3 TPD
- Bio-CNG5 TPD →
- Bio-CNG6 TPD
- Bio-CNG9 TPD
- Bio-CNG10 TPD →
- Bio-CNG12 TPD
- Bio-CNG15 TPD
- Bio-CNG18 TPD
- Bio-CNG20+ TPD
Where Bio-CNG is used
- Vehicle fuel at CNG / OMC retail outlets
- City gas distribution (CNG transport & PNG domestic)
- Industrial heating and boilers
- Captive fleets: buses, tractors, trucks
The notified CBG obligation for the CNG and PNG segments (3% in FY 2026-27, rising to 5% from FY 2028-29) creates structural demand for Bio-CNG. Learn about the CBG obligation.
Why choose Biovardhan for your Bio-CNG plant
- Integrated responsibility from digester to dispenser, so no interface gaps between vendors
- In-house manufacturing with about 125,000 sq. ft. of covered infrastructure
- Feedstock-first design backed by our scientists' panel and lab analysis
- Digestate revenue through FOM, LFOM, biochar and pellet solutions
- One-year ramp-up support and long-term O&M
Frequently asked questions
A Bio-CNG plant produces raw biogas from organic waste by anaerobic digestion, purifies it by removing H₂S, moisture and CO₂, and compresses the high-methane gas for use as a renewable substitute for CNG in vehicles, industry and city gas networks.
Yes. Bio-CNG and Compressed Biogas (CBG) refer to the same product: purified, compressed biogas with properties similar to fossil CNG.
Bio-CNG plant cost depends on capacity, feedstock, digester design, upgrading technology and offtake mode. See our CBG / Bio-CNG plant cost guide for the cost drivers, or contact us for a project-specific estimate.
Bio-CNG plants become profitable when feedstock supply is secured, gas offtake is assured and digestate is monetised as organic manure. The GOBARdhan unified scheme (2026) improves bankability through assured offtake, pricing and capital assistance for eligible projects.
Eligible greenfield CBG/Bio-CNG projects can receive capital assistance of up to ₹2 crore per TPD under the GOBARdhan National Unified Scheme, subject to notified guidelines. See the GOBARdhan subsidy guide.