LNG in industry as an alternative to pipeline gas – applications in cogeneration and energy technologies

LNG is natural gas (primarily methane) that has been cooled to approximately -162°C, causing it to liquefy. In its liquid form, the fuel’s volume is reduced by about 600 times compared to its gaseous state, allowing for efficient transport and storage.

From a chemical standpoint, LNG and pipeline natural gas are virtually identical fuels—the differences lie mainly in their physical properties and delivery methods. LNG is characterized by:

• high purity (typically higher than pipeline gas),
• a stable composition (mostly methane, with minimal heavier hydrocarbons),
• high calorific value (often slightly higher than pipeline gas, depending on the source).

Thanks to these properties, LNG can serve as a viable alternative to pipeline natural gas and effectively fuel equipment designed for gas operation.

The use of LNG in industry is particularly justified in several common scenarios. The first is the lack of technical feasibility to connect to the gas grid — for example, due to long distances from existing infrastructure or insufficient transmission capacity. In such cases, building a pipeline connection may be economically unjustifiable or impossible within an acceptable timeframe.

A second scenario is the need for rapid deployment of gas-based installations, such as cogeneration or other generation assets. While grid connection processes can take several years, LNG infrastructure can typically be implemented within several to a dozen months, making it an effective bridging solution.

LNG may also be considered in projects where pipeline construction is difficult to justify economically. However, it should be noted that LNG supply often requires advance demand planning, which may limit flexibility in cases of highly variable or unpredictable consumption.

Liquefied natural gas can also serve as a backup fuel, enhancing energy security in case of interruptions in pipeline gas supply. However, there is a technical constraint: LNG must be stored at around -162°C to remain in liquid form. To maintain these conditions, cryogenic storage tanks are used.

These are typically double-walled structures (inner steel tank plus outer shell) that:

• have insulation or vacuum between the walls,
• are equipped with pressure and temperature control systems.

While LNG can be stored, it is not without losses. Even with excellent insulation, some heat ingress occurs, causing a portion of the LNG to evaporate over time. This results in boil-off gas (BOG), which must be managed—for example, by consuming it in the installation, compressing it, or flaring it in emergency situations.

In the context of cogeneration, LNG enables the deployment of gas-fired units in locations previously excluded due to lack of infrastructure. After regasification, the fuel can supply gas engines or turbines, allowing for the simultaneous production of electricity and heat.

Similarly, LNG can be used to fuel:

• steam and hot water boilers,
• industrial furnaces,
• drying installations,
• processes requiring a stable and clean gaseous fuel.

A major advantage is the ability to achieve fuel parameters comparable to high-methane natural gas, facilitating integration with existing technologies.

In Poland, the LNG supply chain is based on several infrastructure elements. A key role is played by the LNG terminal in Świnoujście, which receives liquefied gas transported by sea from various regions, including Qatar, the United States, and Norway. After regasification, part of the gas is fed into the national transmission system, while another portion may be re-liquefied on a small scale or transferred to road transport.

For industrial consumers, LNG is delivered by cryogenic tanker trucks. These specialized trailers maintain very low temperatures and appropriate pressure conditions. In large industrial facilities, this translates into regular deliveries - ranging from several to even a dozen or more shipments per day, depending on demand.

Poland also operates small-scale LNG installations, which support distribution on a smaller scale and increase the accessibility of this solution for industrial users.

An important aspect of LNG technology is its compatibility not only with fossil natural gas but also with bio-LNG, i.e., liquefied biomethane. Biomethane is produced by upgrading biogas (e.g., from agricultural, municipal, or industrial waste fermentation) and can then be liquefied similarly to natural gas.

From the perspective of industrial installations, there is no significant technological difference - after regasification, the fuel has parameters equivalent to high-methane gas and can supply the same equipment, including cogeneration units. The key difference lies in the carbon footprint: biomethane is a renewable fuel, and its use can significantly reduce CO₂ emissions, especially when sourced locally from waste streams.

Importantly, unlike systems based solely on certificates of origin, the use of bio-LNG through physical delivery ensures the actual consumption of renewable fuel on-site. In practice, this means LNG can serve not only as an infrastructure solution but also as a component of decarbonization strategies, enabling a gradual transition from natural gas to renewable fuels without requiring changes to end-use technologies.

To utilize LNG as a fuel, an industrial plant must be equipped with appropriate infrastructure. Key components include:

• a cryogenic storage tank,
• unloading systems for tanker trucks,
• regasification systems,
• gas pressure reduction and metering units,
• safety systems (valves, detection systems, emergency venting).

LNG tanks are designed as thermally insulated, often double-walled structures to minimize evaporation losses. Nevertheless, some LNG naturally evaporates (boil-off gas) and must be properly managed - either by consumption in the installation or recompression.

A critical element of the system is regasification, which converts LNG from liquid to gaseous form. This process involves heating the liquefied gas in specialized vaporizers. In practice, several technological solutions are used:

• ambient air vaporizers (using heat from the surroundings),
• water bath vaporizers (using process water),
• forced circulation vaporizers (for higher capacities).

After vaporization, the gas is brought to the required pressure and temperature and then supplied to end-use installations. At this stage, its parameters meet the requirements of industrial equipment.

From a cost perspective, LNG is typically more expensive than pipeline natural gas due to liquefaction, transport, and regasification costs. However, a proper economic assessment should not be limited to fuel price alone. In many cases, LNG proves economically justified due to: avoidance of high pipeline connection costs, faster project implementation and earlier realization of savings, greater investment flexibility during project planning and reduced risk of high upfront infrastructure costs under uncertain demand conditions.

Demand profile is also a critical factor - while very large and stable consumption generally favors pipeline connections in the long term, LNG performs well as a transitional solution or in locations remote from gas infrastructure.

LNG represents a mature and increasingly widespread technological alternative to pipeline natural gas, enabling the deployment of gas-based solutions in industry regardless of access to transmission infrastructure. This is particularly relevant for cogeneration systems, which require a stable, high-quality fuel.

Although LNG involves higher operating costs, its advantages include shorter implementation time, greater investment flexibility, and the ability to execute projects in previously inaccessible locations. In practice, LNG often serves as a bridging solution until a pipeline connection is established or as part of a broader energy diversification strategy within industrial facilities.