LNG (Liquefied Natural Gas)

LNG stands for Liquefied Natural Gas. It is natural gas that has been cooled to approximately −162 °C and converted into a liquid state. The exact liquefaction temperature depends on the composition of the natural gas and the pressure conditions.

The main component of LNG is methane (CH₄). It may also contain small amounts of other hydrocarbons such as ethane, propane, and butane, as well as nitrogen. The exact composition varies depending on the origin of the natural gas and how it is processed.

LNG is neither a chemical substance in its own right nor a fuel produced through chemical conversion. During liquefaction, it is primarily the physical state of the natural gas that changes. Its fundamental chemical composition remains largely unchanged.

LNG is produced from natural gas, which is first extracted and then processed for liquefaction. During this process, water, carbon dioxide, and other undesirable components—which could cause technical problems at the very low processing temperatures—are removed.

The purified natural gas is then cooled in several process steps until it becomes liquid at approximately −162 °C. Liquefaction significantly reduces its volume. One cubic meter of LNG corresponds to approximately 600 cubic meters of natural gas in its gaseous state, although the actual ratio depends on the specific conditions of reference.

This reduction in volume is the technical basis for the economical transport of large quantities of natural gas by sea. LNG is stored in specially insulated tanks and transported to import terminals by LNG tankers. There, it can be temporarily stored and converted back to its gaseous state by applying heat. This process is known as regasification.

After regasification, the natural gas can be fed into suitable gas networks and made available for various energy and industrial applications.

The international LNG supply system thus connects natural gas-producing regions with consumer markets that are not linked by a continuous pipeline network.

The properties of LNG stem primarily from its composition, its low storage temperature, and its liquid state.

LNG is a cryogenic liquid consisting primarily of methane. Therefore, special technical requirements for tanks, pipelines, and safety equipment must be taken into account during storage and transport.

Key properties include:

• Temperature: LNG is maintained at approximately −162 °C at near-atmospheric pressure.

• Composition: The main component is methane; other gas components may be present in smaller proportions.

• Volume: In its liquid state, LNG requires only about one-sixth of the volume of natural gas in its gaseous state.

• Storage: Specially insulated containers designed for cryogenic temperatures are required for transport and storage.

• Vaporization: When heat is applied, some of the LNG can return to a gaseous state. The resulting gas is called boil-off gas.

LNG itself is not immediately flammable in its liquid state. Only when it vaporizes and the natural gas mixes with air in a suitable concentration ratio can a flammable gas-air mixture form.

When handling LNG, there are additional hazards due to the extremely low temperatures. Therefore, special technical and operational safety requirements apply to storage, transport, handling, and use.

LNG is used in various sectors of the energy supply. It plays a central role in the international transportation of natural gas. Liquefaction makes it possible to connect production regions with consumer markets without the need for continuous natural gas pipelines.

After delivery to LNG terminals, the liquefied natural gas is often regasified and then distributed via existing gas networks. The gaseous natural gas can then be used, for example, in industrial processes, power plants, and district heating systems.

In addition, LNG is also used directly as a motor fuel or combustion fuel . In shipping, it is used in ship engines designed for this purpose. For this, ships require suitable LNG tanks, supply systems, and appropriate engine technology. Depending on the engine design, dual-fuel systems can also be used.

Certain heavy-duty commercial vehicles can also use LNG as fuel, provided that their engines, tanks, and refueling infrastructure are designed for it. Technically, its use differs from that of conventional liquid fuels.

The climate impact of LNG must be considered in a nuanced way. Compared to certain conventional fuels, its combustion can result in lower emissions of certain air pollutants. However, extraction, processing, liquefaction, transport, and potential methane emissions are also relevant to the overall greenhouse gas footprint. Methane slip, in particular, can significantly influence the climate impact.

The actual environmental and climate impact therefore depends on the specific supply chain and the technology used.

LNG is often equated with LPG, CNG, or liquefied gas in general. However, these terms refer to different energy sources or different forms of storage.

LNG (Liquefied Natural Gas): LNG is liquefied natural gas and consists primarily of methane. Liquefaction occurs through rapid cooling to approximately −162 °C. LNG is used primarily for the international transport of natural gas and in suitable mobile applications.

LPG (Liquefied Petroleum Gas): LPG refers to liquefied petroleum gas, which consists primarily of propane and butane or mixtures thereof. Unlike LNG, LPG can be liquefied at ambient temperature using relatively moderate pressure. LPG is used, among other things, for heating, cooking, in industry, and as automotive fuel.

CNG (Compressed Natural Gas): CNG is compressed natural gas. Unlike LNG, it remains in a gaseous state and is stored under high pressure. CNG is used, among other things, in vehicles equipped to run on it.

Natural Gas: Natural gas is a naturally occurring mixture of gases, the main component of which is methane. LNG and CNG are different forms of processing or storage of this gas.

The terms LNG and LPG should therefore not be used interchangeably. They differ in their chemical composition as well as in storage conditions, transportation methods, and typical applications.

LNG stands for Liquefied Natural Gas and refers to natural gas that has been liquefied through cooling. This energy source consists primarily of methane and becomes liquid at temperatures of approximately −162 °C. This significantly reduces its volume, allowing large quantities of natural gas to be transported in specially equipped tankers and storage tanks.

LNG is used primarily in the international natural gas market. After regasification, it can be supplied via gas networks for energy use. In addition, it can be used directly as fuel in appropriately equipped ships and heavy-duty vehicles.

LNG differs from LPG primarily in its methane-based composition and the required cryogenic storage conditions. When assessing its environmental and climate impact, the entire supply chain and potential methane emissions must be taken into account in addition to combustion.