_Filling_Station,_Maharastra,_India_(1).jpg){kind=link}
Compression
Multi-stage gas compressors with intercooling raise pipeline gas to storage pressure. Filters and drying stages remove moisture and contaminants before compression.
The basics
What is CNG?
Compressed natural gas (CNG) is natural gas stored at high pressure as a fuel. Natural gas consists mainly of methane. At a filling station or gas plant it is compressed from pipeline pressure to a much higher pressure — typically around 200 to 250 bar — so a useful amount of energy fits inside a vehicle cylinder or a station storage cascade.
Because it is a gas, it burns differently from liquid fuels. In a correctly converted engine, CNG burns cleanly and can reduce tailpipe emissions such as carbon monoxide, unburnt hydrocarbons and particulate matter compared with running the same engine on petrol or diesel.
In Bangladesh, CNG powers three-wickshaws, cars, buses and commercial fleets, and natural gas is also supplied directly to industrial users. The abbreviation “CNG” has even become the everyday name for the auto-rickshaws that run on it.
How it works
From pipeline to cylinder
Three stages turn piped natural gas into vehicle fuel. Each one has its own equipment and its own safety rules.
Storage
High-pressure cascade storage — banks of cylinders filled in sequence — holds the gas so vehicles can be refuelled quickly without waiting for the compressor to keep up.
Dispensing
A dispenser with a hose and breakaway coupling fills the vehicle cylinder, with pressure monitoring and overfill protection built into the process.
Uses
Where CNG is used
Vehicles
Cars, buses, auto-rickshaws and commercial fleets converted to bi-fuel operation. The vehicle keeps its petrol system and switches to gas with a changeover valve.
Factories
Boilers, furnaces, ovens and dryers in textile, food, brick and ceramic production. Gas may arrive by pipeline or compressed and delivered by truck.
Gas engines
Standalone gas engines and generator sets run on CNG where reliable power or combined heat and power is needed — a growing use as energy costs rise.
Advantages & limits
Benefits and limitations
An honest summary: CNG solves real problems, but it is not a universal answer.
Benefits
- Cleaner burning. Lower tailpipe carbon monoxide, particulates and unburnt hydrocarbons than petrol or diesel.
- Lower CO2 per unit of energy than other fossil fuels, because methane is hydrogen-rich and burns efficiently.
- Cost advantage where gas is cheap. Where pipeline gas is priced below liquid fuels, fuel cost per kilometre or per unit of heat is usually lower.
- Safer storage behaviour. Being lighter than air, leaked gas disperses upward rather than pooling on the floor — if ventilation is adequate.
- Simple logistics for industry. Piped or delivered gas avoids handling and storing liquid fuels on site.
Limitations
- Lower energy density. A CNG cylinder stores much less energy by volume than a petrol tank, so range is shorter and cylinders are bulky.
- Higher upfront cost. Conversion, cylinder certification and station equipment all cost money before the first kilometre is driven.
- Refuelling takes time and depends on a station network; long journeys need planning.
- Not emission-free. Carbon dioxide is still produced, and unburnt methane (“methane slip”) from poorly maintained engines is a real climate concern.
- Supply is not guaranteed. Gas pressure and availability can vary, which matters for both drivers and factories.
Cost figures change. Fuel prices and savings move with tariff decisions, so this site does not quote fixed numbers. Current figures are shown as placeholders until they are verified — see the running-cost section on the CNG for Automotive page.
Safety
Safety comes from standards, not luck
CNG is stored at very high pressure, so safety depends on certified equipment and regular inspection: cylinders with a defined service life, pressure relief devices, correct hose and fitting specifications, ventilation, and periodic re-testing of cylinders and stations.
- Only certified cylinders and components should be installed
- Cylinders must be re-tested at the interval set by the regulator
- Stations and workshops need trained operators and safety procedures
- Any smell, hiss or visible damage should be treated as urgent
- Workshops and storage areas must be ventilated — gas is lighter than air and accumulates at high points
Learn how this applies to vehicles on the CNG for Automotive page, and to factories on the CNG for Industry page.
Role in Bangladesh
Built on domestic gas
Bangladesh turned its natural gas reserves into one of the largest CNG vehicle fleets in the world. Auto-rickshaws, taxis and buses in the major cities run almost entirely on gas, supported by a dense network of filling stations, conversion workshops and re-testing centres.
The fleet grew through government policy from the late 1990s onwards: converting vehicles was cheaper and cleaner than running them on petrol, and directives against older, more polluting three-wheelers and taxis pushed the transition further.
Industry shares the same resource. Factories depend on pipeline gas for heat, so periods of shortage or low pressure directly affect production — which is why delivered CNG and on-site storage are part of the industrial energy picture.
Where to go next
Explore the topic further
CNG for Automotive
History, conversion, cylinders and daily use in vehicles.
CNG for Industry
Gas supply for factories, boilers and furnaces.
Products & Services
Equipment, stations, workshops and re-testing.