CNG and LNG

What are CNG and LNG?

CNG (Compressed Natural Gas) and LNG (Liquefied Natural Gas) are both forms of natural gas used as fuel in the transport sector. Natural gas consists primarily of methane (CH₄) and is known for its cleaner combustion compared with traditional fossil fuels such as petrol and diesel.

CNG is produced by compressing natural gas to a pressure of around 200–250 bar. This compression significantly reduces the volume of the gas, making it possible to store and transport large quantities of natural gas in pressurised tanks. CNG is particularly popular in city buses, refuse collection vehicles and light vehicles, as it requires less storage space and is more readily available.

LNG is produced by cooling natural gas to around -162 degrees Celsius, at which point it is converted into a liquid form. This cooling process reduces its volume by approximately 600 times compared with its gaseous state, making LNG ideal for transport over long distances. LNG is stored in specially designed cryogenic tanks that can maintain the extremely low temperature. LNG is often used in heavy transport, such as lorries and ships, which require large quantities of fuel for long journeys.

Benefits and Emissions:

• Environmental benefits: The use of CNG and LNG reduces CO₂ emissions by up to 20–30% compared with diesel and petrol. Furthermore, they produce fewer NOx and particulate emissions, which helps to improve air quality.
• Energy utilisation: Natural gas offers higher energy efficiency, which means that vehicles can travel further on the same amount of fuel.
• Financial Savings: Natural gas is often cheaper than traditional fuels, resulting in significant operational savings for transport companies.

Storage and Transport of CNG and LNG:

• CNG: CNG is stored in high-pressure cylinders designed to withstand high pressures. These cylinders can be fitted to vehicles or used for stationary storage.
• LNG: LNG is stored in cryogenic tanks, which ensure that the gas is kept at the required low temperature. Transporting LNG requires special vehicles and ships fitted with cryogenic systems.

Applications in the transport sector:

CNG and LNG are used in a range of different modes of transport. City buses and light commercial vehicles often use CNG due to its wide availability and lower storage costs. Heavy goods transport and shipping prefer LNG because of its high energy density and ability to be transported over long distances without frequent refuelling.

By understanding the technical aspects, transport companies can make informed decisions about switching to these sustainable fuels. This will not only reduce their environmental impact, but also improve the cost-effectiveness of their operations and future-proof their fleets.

TSG works with selected partners to provide the necessary expertise required for the installation and maintenance of equipment used for the distribution of CNG and LNG.