# CNG, LPG and biogas distribution: How it works

Why methane must be squeezed while propane only needs pressure

Source page: https://www.materialinsights.org/energy/e_cng_lpg/explain/

What this tab covers How the energy actually moves, step by step: the science that makes it work and the engineering that makes it practical.

Where there are no pipes, gas travels in pressure vessels: methane squeezed to about 250 bar (CNG), propane and butane kept liquid under modest pressure (LPG), and upgraded biogas injected into the grid or bottled.

#### Step by step

1. **Compress or liquefy at the source**CNG compressors raise pipeline gas to about 250 bar. LPG, separated from natural gas or refinery streams, stays liquid simply by being held under pressure.
2. **Move in bulk**CNG fills banks of composite cylinders on trailers or containers. LPG moves in very large gas carriers (VLGCs) at sea, rail cars, road tankers and some pipelines.
3. **Stock and fill**CNG stations keep a cascade of high, medium and low pressure cylinders for fast filling; LPG is stored in spheres or bullet tanks and bottled into cylinders.
4. **Deliver the last mile**Trucks, vans and handcarts take cylinders to homes, shops and farms; empties come back for refilling.
5. **Biogas route**Biogas from digesters is stripped of carbon dioxide and impurities to near-pure methane (biomethane), then injected into gas networks or compressed into cylinders.

#### The science

Methane cannot be liquefied by pressure alone at room temperature, so CNG relies on squeezing: at 250 bar it is roughly 250 times denser than at atmospheric pressure (ideal-gas estimate, calculated; real methane deviates somewhat). Propane and butane have larger molecules that attract each other more, so a few bar turns them liquid at ordinary temperatures, making LPG far easier to store and carry. Biogas is roughly half methane, half carbon dioxide; removing the carbon dioxide gives biomethane.

#### The engineering

CNG cylinders range from all-steel (Type 1) to carbon-fibre wrapped plastic liners (Type 4), about 75% lighter than steel. LPG cylinders are welded steel or composite with a valve and pressure relief device; terminals use spheres, and ships use refrigerated or pressurised tanks. Biomethane upgrading uses water scrubbing, membranes, amines or pressure-swing adsorption, then a grid entry unit checks quality and odorises the gas.

#### Key numbers
 CNG module working pressure 250 bar at 15 C, emptied down to 10 bar^[7](https://www.cngservices.co.uk/wp-content/uploads/HA-MP_XSTORE-3_2025-final.pdf) Gas carried by a 40-foot Type 4 CNG module 8,720 kg (11,970 cubic metres) in 114 cylinders^[7](https://www.cngservices.co.uk/wp-content/uploads/HA-MP_XSTORE-3_2025-final.pdf) World LPG supply, 2024 more than 370 million tonnes^[1](https://www.argusmedia.com/en/news-and-insights/latest-market-news/2732380-q-a-global-lpg-growth-defies-2024-headwinds) VLGC fleet, end 2025 421 ships, 105 on order^[2](https://www.bwlpg.com/media/events/q4-2025-earnings-presentation/) Biomethane injected into European gas grids, gas year to September 2025 43.2 TWh (about 4.3 bcm, calculated)^[8](https://www.entsog.eu/sites/default/files/2026-02/ENTSOG%20Report%20on%20Annual%20Renewable%20Gas%20Injections%20into%20Gas%20Networks%202026.pdf)

#### Sources

1. [Q&A: Global LPG growth defies 2024 headwinds (on the WLGA and Argus Statistical Review of Global LPG 2025)](https://www.argusmedia.com/en/news-and-insights/latest-market-news/2732380-q-a-global-lpg-growth-defies-2024-headwinds) Argus Media, 2025
2. [Q4 2025 Earnings Presentation](https://www.bwlpg.com/media/events/q4-2025-earnings-presentation/) BW LPG, 2026
3. [Mobile Pipeline X-STORE ADR gas modules datasheet](https://www.cngservices.co.uk/wp-content/uploads/HA-MP_XSTORE-3_2025-final.pdf) Hexagon Agility, 2025
4. [ENTSOG Report on Annual Renewable Gas Injections into Gas Networks 2026](https://www.entsog.eu/sites/default/files/2026-02/ENTSOG%20Report%20on%20Annual%20Renewable%20Gas%20Injections%20into%20Gas%20Networks%202026.pdf) ENTSOG, 2026

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_cng_lpg/index.md)
- [Overview](https://www.materialinsights.org/energy/e_cng_lpg/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_cng_lpg/correlation/index.md)
- [Efficiency and losses](https://www.materialinsights.org/energy/e_cng_lpg/efficiency/index.md)
- [Technology advances](https://www.materialinsights.org/energy/e_cng_lpg/advances/index.md)
- [Value chain](https://www.materialinsights.org/energy/e_cng_lpg/valuechain/index.md)
- [Geopolitics and regulation](https://www.materialinsights.org/energy/e_cng_lpg/geopolitics/index.md)
- [Unit economics](https://www.materialinsights.org/energy/e_cng_lpg/economics/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_cng_lpg/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_cng_lpg/links/index.md)