India produces enormous quantities of agricultural residues, cattle dung, food waste, press mud and other organic waste every year. Much of this material has traditionally been treated as a disposal problem or has had limited economic value.

A Compressed Biogas (CBG) Plant provides a way to convert suitable organic waste into a renewable fuel while also producing digestate that can be processed into organic manure.

The basic idea is simple:

Organic Waste → Biogas → Purification → Upgrading → Compression → CBG

But a commercial CBG plant is much more than a digester. Feedstock preparation, anaerobic digestion, gas cleaning, upgrading, compression, storage, digestate management and gas offtake all have to work together.

The sector is also entering a new phase in India. On 6 August 2026, the Union Cabinet approved GOBARdhan, the National Circular Bioenergy Scheme, with a total outlay of ₹23,731 crore for FY 2026–27 to FY 2035–36. The scheme is designed to provide an integrated framework for scaling up CBG production through measures including assured demand, stable pricing, capital assistance, pipeline infrastructure, credit support and technology development.

For anyone considering a CBG project, this makes it an interesting time to understand how the complete business and technology actually work.

What Is CBG?

CBG stands for Compressed Biogas.

Biogas is produced when biodegradable organic material is broken down by microorganisms in an oxygen-free environment. The raw gas contains methane along with carbon dioxide, hydrogen sulphide, water vapour and other gases.

The gas is then cleaned and upgraded to increase its methane concentration.

After purification and upgrading, the gas is compressed and stored as CBG.

In simple terms:

Biomass / Organic Waste → Anaerobic Digestion → Raw Biogas → Gas Purification → Biogas Upgrading → Compression → CBG

CBG is therefore different from conventional CNG.

CNG generally comes from natural gas.

CBG is produced from renewable organic feedstock through biological and gas-upgrading processes.

Why Is CBG Getting Attention in India?

The CBG opportunity is closely connected with India's agricultural economy and waste-management requirements.

Suitable feedstocks can include agricultural residues, cattle dung, press mud, municipal organic waste and other biomass resources.

The current GOBARdhan framework specifically aims to convert such organic resources into clean fuel, organic manure and economic value.

The Government has set an objective of increasing domestic CBG production by nearly ten times under the new scheme. It also aims to encourage private investment and build a larger circular bioeconomy around organic waste.

This is important because a CBG plant can create value from more than one output:

CBG
Digestate
Organic manure products
Recovered process energy in suitable plant configurations

So the business should not be looked at as simply a gas-production project.

It is better understood as a waste-to-energy and waste-to-value project.

What Raw Materials Can Be Used in a CBG Plant?

Feedstock selection is one of the most important decisions in a CBG project.

Depending on the technology and project conditions, potential feedstocks include:

Cattle dung
Paddy straw
Wheat straw
Napier grass
Maize silage
Sugarcane press mud
Food waste
Vegetable waste
Fruit waste
Agricultural residues
Organic industrial waste
Municipal organic waste
Other suitable biodegradable biomass

The Government's current GOBARdhan framework specifically identifies agricultural residue, cattle dung, press mud, municipal organic waste and other biomass resources as feedstocks that can contribute to the CBG ecosystem.

However, simply having biomass available does not mean it will automatically work well in a CBG plant.

Before selecting the technology, the feedstock should be evaluated for:

Moisture
Total solids
Volatile solids
Organic matter
Fibre content
C:N ratio
Contamination
Biogas potential
Seasonal availability
Transportation distance

This is why feedstock testing should come before final plant sizing.

How Does a CBG Plant Work?

A typical CBG production plant can be divided into several stages.

1. Raw Material Collection

The first step is collecting the feedstock and bringing it to the plant.

This sounds simple, but it can become one of the biggest challenges in a commercial project.

For example, if a plant requires 100 tonnes of biomass every day, it is not enough to know that 100 tonnes of biomass exists somewhere in the surrounding region.

The developer needs to know:

Where is it located?
Who supplies it?
Is it available throughout the year?
How much can actually be collected?
What is its moisture?
What is the transportation cost?
Does it contain soil or other contamination?
What happens during the off-season?

A reliable feedstock supply chain is therefore extremely important.

2. Biomass Preparation

Different feedstocks require different preparation.

Cattle dung may mainly require mixing and slurry preparation.

Paddy straw, wheat straw and other fibrous biomass may require:

Baling
Bale breaking
Cutting
Shredding
Crushing
Size reduction

The objective is to create a feedstock that can be handled consistently and fed into the digestion system.

This is one area where a well-designed biomass-processing system can make a significant difference.

3. Slurry Preparation

Depending on the feedstock, water or recycled process liquid may be added to achieve the required consistency.

The prepared material becomes a slurry or pumpable mixture suitable for feeding into the digester.

The exact solids concentration depends on the feedstock and digestion technology.

4. Anaerobic Digestion

The anaerobic digester is the heart of a CBG plant.

Inside the digester, microorganisms break down biodegradable organic matter in the absence of oxygen.

This produces raw biogas.

Raw biogas generally contains:

Methane
Carbon dioxide
Hydrogen sulphide
Water vapour
Trace gases

Methane is the primary fuel component.

The digestion process also produces digestate, which can subsequently be separated and processed for appropriate manure applications.

5. Raw Biogas Collection

The biogas produced inside the digester is collected through the gas-handling system.

At this stage, it is not yet CBG.

The raw gas needs further treatment because it contains unwanted gases and moisture.

This is where the gas purification section becomes important.

6. Hydrogen Sulphide Removal

Hydrogen sulphide, commonly written as H₂S, is an unwanted component of raw biogas.

It needs to be controlled before the gas enters downstream equipment.

The specific H₂S removal technology depends on the feedstock, gas composition, plant capacity and overall process design.

7. Biogas Upgrading

Raw biogas contains a significant amount of carbon dioxide.

The upgrading system removes carbon dioxide and other unwanted components so that the methane concentration increases.

Different technologies can be used depending on the project, such as:

Membrane separation
PSA
Water scrubbing
Amine-based systems
Other gas-upgrading technologies

There is no single upgrading technology that is ideal for every CBG project.

The selection should consider:

Raw biogas composition
Capacity
Methane recovery
Energy consumption
Gas quality requirements
Capital cost
Operating cost

8. Gas Drying

Moisture is another important consideration.

After upgrading, the gas needs to meet the required quality conditions before entering the high-pressure compression system.

Gas drying and conditioning help protect downstream equipment and maintain the required gas quality.

The applicable gas specification and plant design should be confirmed for the intended CBG application.

9. CBG Compression

Once the biogas has been properly purified and conditioned, it can be compressed.

The compression system raises the gas pressure to the required level for storage and transportation.

The compressed gas is stored in suitable high-pressure cascades.

The compressor, storage system, piping, valves and safety equipment all need to be designed as an integrated high-pressure gas system.

10. CBG Storage and Transportation

The compressed gas can be stored in high-pressure cascades.

Depending on the project, CBG can then be transported through suitable cascade arrangements or supplied through appropriate gas infrastructure.

The commercial arrangement needs to be considered before the plant is designed.

A CBG project should ideally have a clear understanding of:

Who will purchase the gas?
Where will it be delivered?
What gas quality is required?
What pressure is required?
What transportation arrangement will be used?
What measurement and billing system applies?

11. What Happens to the Digestate?

A CBG plant produces another important output besides gas.

After digestion, the remaining material is called digestate.

It can be separated into solid and liquid fractions and processed further.

Depending on its characteristics and applicable requirements, it can be used in organic manure applications.

The Government has been developing the CBG ecosystem around both renewable fuel and organic-manure utilization. The GOBARdhan framework explicitly includes the conversion of organic resources into clean fuel and organic manure.

This means a CBG project should not ignore digestate.

It should be included in the original project planning.

Complete CBG Plant Process Flow

The complete process can be understood as:

Raw Material Collection

↓

Bale Breaking / Shredding / Size Reduction

↓

Slurry Preparation

↓

Anaerobic Digestion

↓

Raw Biogas

↓

H₂S Removal

↓

CO₂ Removal / Biogas Upgrading

↓

Gas Drying

↓

CBG Compression

↓

High-Pressure Storage

↓

Transportation / Dispensing

At the same time:

Digestate → Solid-Liquid Separation → Organic Manure Processing

This is why a CBG plant should be designed as a complete system rather than purchasing a digester and adding other equipment later.

How Much CBG Can Be Produced From 10 Tonnes of Biomass?

This is probably one of the first questions asked by anyone planning a CBG project.

But there is no single fixed answer.

Ten tonnes of:

Paddy straw
Cattle dung
Food waste
Press mud
Napier grass

will not necessarily produce the same amount of biogas or CBG.

The actual calculation depends on the feedstock characteristics.

A proper calculation should follow:

Wet Feedstock

↓

Moisture Analysis

↓

Dry Matter

↓

Volatile Solids

↓

Biogas Yield

↓

Methane Content

↓

Gas Upgrading Recovery

↓

Final CBG Production

This is much more reliable than using a simple tonnes-to-CBG conversion factor.

Why Moisture Is So Important

Suppose a project receives:

10 tonnes of biomass at 30% moisture.

That does not mean the plant is receiving 10 tonnes of dry biomass.

Approximately:

10 tonnes × 70% = 7 tonnes of dry matter

The remaining 3 tonnes is water.

The actual gas potential depends on the biodegradable portion of the dry matter.

This is why moisture testing is essential when calculating:

Digester capacity
Feedstock requirement
Biogas production
CBG production
Transportation
Storage
Project economics

CBG Plant Capacity: How Do You Decide?

One common mistake is to start with:

“I want a 10-ton CBG plant.”

But what does 10 tonnes actually mean?

Is it:

10 tonnes of raw biomass per day?
10 tonnes of dry biomass per day?
10 tonnes of cattle dung?
10 tonnes of organic waste?
10 tonnes of CBG output?

These are completely different things.

The capacity of a CBG plant should be clearly defined in terms of feedstock input and/or gas output.

A proper project calculation should start with:

Available Feedstock → Feedstock Quality → Biogas Potential → Methane Recovery → CBG Output

Only then should the major equipment be sized.

Main Machinery Required for a CBG Plant

A complete CBG project may require the following systems.

Feedstock Handling

Bale breaker
Conveyor
Shredder
Chopper
Crusher
Feed hopper
Magnetic separator or foreign-material protection where required

Slurry Preparation

Mixing tank
Slurry preparation system
Pumps
Agitators
Feeding system

Digestion

Anaerobic digesters
Mixing system
Heating system where required
Gas holder
Digestate handling system

Gas Treatment

H₂S removal system
Gas cooling
Moisture removal
CO₂ removal system
Biogas upgrading system
Gas quality monitoring

CBG Compression

High-pressure compressor
Cascade storage
Gas control system
Filling or dispensing system
Safety systems

Digestate Processing

Solid-liquid separator
Digestate storage
Drying or further processing
Organic manure processing and packing where required

Not every CBG plant needs exactly the same equipment.

The final machinery list should be based on the feedstock and process configuration.

CBG Plant vs Biogas Plant

A normal biogas plant and a CBG plant are related but not identical.

Biogas Plant

Produces raw biogas that can be used locally for applications such as:

Cooking
Heating
Boiler fuel
Power generation

CBG Plant

Takes the biogas process further.

The gas is:

Produced → Purified → Upgraded → Dried/Conditioned → Compressed

The result is CBG suitable for applications that meet the required gas-quality and safety specifications.

Therefore, a CBG plant requires additional gas-treatment and compression infrastructure compared with a basic biogas plant.

CBG vs CNG

This is another common confusion.

CBG	CNG
Compressed Biogas	Compressed Natural Gas
Produced from organic waste	Generally produced from natural gas
Renewable feedstock route	Fossil natural-gas route
Requires anaerobic digestion	Does not require a digester
Requires biogas upgrading	Requires natural-gas compression
Produces digestate	Does not produce digestate
Can contribute to waste management	Primarily a natural-gas fuel

In simple terms:

CNG = Natural Gas + Compression

CBG = Organic Waste → Biogas → Purification → Compression

What Is GOBARdhan?

For anyone planning a CBG plant in India today, GOBARdhan is a major policy framework to understand.

The Union Cabinet approved GOBARdhan as the National Circular Bioenergy Scheme on 6 August 2026, with a total outlay of ₹23,731 crore covering FY 2026–27 to FY 2035–36. The Ministry of Petroleum and Natural Gas is the nodal ministry under the current framework.

The scheme brings together measures intended to support the CBG ecosystem, including:

Assured demand
Stable pricing
Capital assistance
Pipeline infrastructure
Credit support
Technology development
Biomass utilization
Organic manure utilization

The Government has stated that the scheme aims to increase domestic CBG production by nearly ten times.

GOBARdhan Registration for CBG Plants

The GOBARdhan Unified Registration Portal provides registration for CBG/Bio-CNG projects.

According to the Government's 6 August 2026 update, registration through the GOBARdhan Unified Registration Portal is required to avail benefits and support from the Ministry of Petroleum and Natural Gas.

As of 6 August 2026, the Government reported:

1,908 CBG/Bio-CNG plants registered
217 plants commissioned
339 plants under construction
Approximately 0.4 MMSCMD production from commissioned plants

These numbers show the scale of the CBG ecosystem that has already developed in India.

A later government update reported 1,929 registered CBG/Bio-CNG plants as of 13 August 2026, including 217 commissioned and 357 under construction.

Is There a Fixed CBG Subsidy Under GOBARdhan?

This is where CBG project developers need to be careful.

It is better not to assume that every CBG plant receives one fixed subsidy amount.

The current GOBARdhan framework contains different components and forms of support, and the component-wise operational guidelines were issued by MoPNG on 16 September 2026.

The applicable support depends on the project, component, eligibility and relevant operational guidelines.

Therefore, before including subsidy as guaranteed income in a project report, the developer should check the latest applicable GOBARdhan guidelines.

CBG Pricing Under the Current GOBARdhan Framework

CBG pricing is another important part of project economics.

In an official clarification published on 29 August 2026, the Government stated that under the GOBARdhan Scheme, the CBG procurement price had been fixed at ₹2,110 per MMBtu. The Government also clarified that this is the procurement price paid to CBG producers and should not be confused with the retail price paid by CNG or household PNG consumers.

Because pricing arrangements and applicable conditions can change, project developers should always use the latest official procurement terms when preparing financial models.

What Should You Check Before Starting a CBG Plant?

Before investing in a CBG plant, I would recommend checking these points carefully.

1. Raw Material

What exactly will you process?

Do not simply write “biomass.”

Specify the actual feedstock.

2. Daily Availability

How many tonnes are reliably available every day?

3. Moisture

What is the actual moisture percentage?

4. Organic Matter

How much biodegradable material is present?

5. Biogas Potential

Has the feedstock been tested?

6. Transportation

How far does the biomass need to travel?

7. Gas Offtake

Who will purchase the CBG?

8. Digestate

What will you do with the solid and liquid digestate?

9. Land and Utilities

Is there enough land, water and electricity for the project?

10. Approvals

What environmental, gas, pressure, fire, electrical and local approvals apply to the proposed project?

11. GOBARdhan Registration

Has the project been evaluated under the current GOBARdhan framework and registration requirements?

12. Technology

Has the technology provider demonstrated the proposed process on similar feedstock?

These questions can save a project from many problems later.

Why Feedstock Is the Starting Point for a CBG Project

When people talk about CBG plants, they often start with the digester size.

In practice, the first question should be:

“What raw material do I have?”

Suppose one company has access to cattle dung and another has access to paddy straw.

Both may want a CBG plant.

But their:

Feed preparation
Digester design
Solids handling
Mixing
Gas yield
Plant equipment
Operating cost

can be very different.

This is why a CBG plant should be engineered around the feedstock rather than simply selecting a standard plant capacity.

Can Agricultural Waste Be Converted Into CBG?

Yes, suitable agricultural residues can be used as feedstock for CBG production.

However, fibrous biomass such as paddy straw and wheat straw may require considerable preparation before anaerobic digestion.

Depending on the material, the process may include:

Baling → Bale Breaking → Cutting/Shredding → Size Reduction → Mixing → Pretreatment → Anaerobic Digestion

The exact process depends on the feedstock characteristics and digestion technology.

This is an area where biomass-processing expertise becomes particularly valuable.

CBG as a Waste-to-Wealth Opportunity

The real attraction of CBG is not only the gas.

Consider the complete chain:

Agricultural Residue

↓

Collection

↓

Processing

↓

Anaerobic Digestion

↓

Biogas

↓

Upgrading

↓

CBG

Digestate

↓

Organic Manure

This creates the possibility of converting one waste stream into multiple useful outputs.

That is the basic idea behind the waste-to-wealth model.

Proveg Engineering and CBG Projects

At Proveg Engineering & Food Processing Pvt. Ltd., our core expertise is in biomass processing and waste-to-value machinery.

Our project areas include:

Biomass Pellet Plants
Biochar Plants
Carbonization Plants
Charcoal Plants
Biomass Processing
Biofertilizer Plants
Waste-to-Value Solutions

For CBG projects, our approach is to start with the actual biomass and project requirement rather than treating every feedstock in the same way.

A CBG project should be evaluated around:

Raw Material → Preparation → Digestion → Biogas → Upgrading → Compression → CBG → Digestate

This integrated approach helps the project developer understand the complete process before finalizing equipment and investment.

Final Thoughts

A CBG plant is much more than an anaerobic digester.

It is a complete waste-to-energy system involving:

Feedstock Collection

→ Biomass Preparation

→ Anaerobic Digestion

→ Biogas Treatment

→ Gas Upgrading

→ Compression

→ CBG Storage

→ CBG Offtake

and, alongside it:

Digestate Processing → Organic Manure

With the approval of the GOBARdhan National Circular Bioenergy Scheme in 2026, the Indian CBG sector now has a consolidated national framework covering important areas such as demand, pricing, capital assistance, infrastructure, financing and technology development.

For anyone planning a CBG project, the best place to start is not with a machine quotation.

Start with the feedstock.

Understand its quantity, moisture, organic content, biogas potential and availability. Then determine the CBG output, gas-upgrading requirement, digestate utilization, offtake arrangement and finally the plant configuration.

That is the foundation of a practical CBG project.

Proveg Engineering – Biomass & Waste-to-Value Solutions

Proveg Engineering & Food Processing Pvt. Ltd.

Website: www.provegengineering.in
Email: provegengineering@gmail.com
Sales: +91 92519 91977