Over recent years, CNG has become one of the most talked-about alternative energy options in the transport sector. However, there is still confusion about what it really is, how it works, and what benefits it brings compared to other fuels. If you are wondering what CNG is, what it is used for, and why it is becoming increasingly important, here you will find a clear, comprehensive explanation.
What does CNG mean?
The acronym CNG stands for compressed natural gas. It is the same natural gas as used in residential and industrial applications, but compressed to high pressures (200 to 250 bar), enabling storage in cylinders and use primarily as vehicle fuel.
Unlike other petroleum-derived fuels such as petrol or diesel, CNG comes from a cleaner fossil source, with a higher methane (CH₄) content and fewer polluting compounds.
What is CNG used for?
The main use of CNG is in the transport sector. It is found in a wide range of applications:
- Private passenger vehicles: cars modified with conversion kits.
- Public transport: urban buses seeking to reduce emissions in large cities.
- Delivery and logistics fleets: medium- and heavy-duty trucks prioritising fuel efficiency and reduced environmental impact.
- Industrial use: in machinery or internal transport in factories and ports.
Some countries also promote CNG as a strategic alternative to reduce dependence on imported fuels.
Benefits of CNG compared to other fuels
When users ask about the benefits of CNG, they typically want to understand its advantages compared to alternatives such as petrol, diesel, or other gaseous fuels like LPG. The main benefits are:
1. Lower environmental impact
CNG emits up to 25% less CO₂ than petrol, and reduces pollutants such as sulphur or particulate matter to almost zero. This makes it a more sustainable alternative.
2. Reduced fuel cost
In many countries, CNG is cheaper per kilogram of equivalent energy, leading to substantial savings in vehicle fuel expenses.
3. Less engine wear
As a cleaner fuel, it produces fewer combustion residues, extending the lifespan of engine oil and components.
4. Proven safety
CNG is stored in high-strength cylinders. Since it is lighter than air, it dissipates rapidly in the event of a leak, reducing the risk of explosive accumulation.
5. Less noise
CNG engines typically operate more quietly, contributing to a reduction in urban noise pollution.
Difference between CNG and LPG
CNG is often mistaken for LPG (Liquefied Petroleum Gas), as both serve as alternative fuels. However:
- CNG is primarily methane derived from natural gas, and is stored in compressed form.
- LPG is a petroleum-derived mixture of propane and butane, and is stored as a liquid under moderate pressure.
While both serve similar applications, CNG offers cleaner combustion, whereas LPG has a higher volumetric energy density.
Challenges and limitations of CNG
Although CNG offers many benefits, it also faces challenges that prevent widespread adoption:
- Limited infrastructure: in many countries, the number of refuelling stations is still limited.
- Vehicle space: the storage cylinders are bulky, meaning less space in the boot.
- Less range: the range per fill is usually more limited than with petrol or diesel, although it can be combined with liquid fuels in dual-fuel systems.
The future of CNG
The future of CNG will depend on factors such as the expansion of infrastructure, government commitment to cleaner energy, and integration with solutions like biomethane, which enables renewable gas production from organic waste.
CNG therefore offers not only a cleaner, cost-effective alternative to traditional fuels, but also serves as a transitional technology towards more sustainable mobility.
Now that you know what CNG is, its main uses, and the benefits it offers, it is clear why this fuel is gaining prominence in the transport sector. Compressed natural gas is positioning itself as a transition fuel between conventional fossil fuels and emerging renewable alternatives, providing advantages in cost, efficiency, and sustainability.
Although it is not without its challenges, its role as a transitional energy source makes it a key resource in the pursuit of a future with a lower environmental impact.