As soon as you start reading, questions come to mind: what exactly is an LNG terminal, why is it important and just how does it process cold gas at -160°C? If you’re looking for clear, detailed and non-technical answers, this article is for you.
What is an LNG terminal?
An LNG terminal – also known as a regasification terminal or regasification plant – is an industrial facility whose main purpose is to receive Liquefied Natural Gas (LNG), store it safely and then convert it back into gas for the distribution network or for local consumption.
These terminals can be:
- Terrestrial, built on land, with cryogenic tanks and pipelines for regasification.
- Floating or FSRU (Floating Storage and Regasification Units): floating units that perform the same functions without the need for a fixed plant.
Both types allow LNG, which has been liquefied at extremely low temperatures, to return to its gaseous state and be used for domestic, industrial or gas network requirements.
Stages of LNG terminal operation
1. Reception and unloading
When an LNG carrier arrives, it is connected by cryogenic arms to the terminal jetty to transfer the LNG to specialised tanks.
2. Cryogenic storage
LNG is stored in double tanks, which are highly insulated and designed to maintain temperatures close to -160°C. These tanks are protected with materials such as perlite and special steel to prevent leaks and thermal losses.
3. Boil-off and Reliquefaction
During storage, part of the gas evaporates (boil-off phenomenon). This gas is mixed in the reliquefier, using its energy to maintain the balance inside the tank and avoid waste.
4. Regasification
The key to the process: LNG is pumped through vaporisers – which use seawater or air – to raise the temperature to 0-10°C, transforming it back into natural gas. Here:
- The pipes that transport the LNG are immersed in water, which reduces their temperature by a few degrees through heat exchange.
- The resulting gas is pressurised and prepared for injection into the network.
5. Measurement, regulation and odourisation
Before reaching consumers, the gas passes through stations where its flow is measured, its pressure is regulated, and an odorant is added for leak detection.
6. Injection and distribution
Lastly, the natural gas goes into pipelines for distribution to residential and industrial customers or power plants. In some cases, it is transported in tankers as part of a virtual pipeline.
What does an LNG terminal do?
LNG terminals serve three main functions:
- Guarantee energy supply when there are no pipelines or at peak demand.
- Improve the reliability of supply, as LNG can be stored and regasified as needed.
- Ensure the flexibility of the system, allowing it to adapt to market and climate fluctuations.
Types of terminals
- Terrestrial: with fixed infrastructure and large storage capacity.
- Floating (FSRU): versatile, quick to deploy, ideal for situations in which building a fixed plant would be challenging.
- Satellite plants: operate alongside a main terminal, but are dedicated to local supply.
Key benefits
- Peak consumption management: allow peak demand to be covered in winter or in urgent situations.
- Reduction of energy dependence: facilitate imports from different suppliers.
- Sustainability: LNG emits 20-25% less CO₂ compared to fuel oil and almost eliminates NOx, SOx and particulates.
Challenges and critical issues
- Environmental impact: the use of seawater for vaporisation may affect nearby marine ecosystems.
- Infrastructure costs: significant investment required for cryogenic tanks, pumping systems and vaporisers.
- Operational safety: require stringent control measures for temperature, pressure and potential leaks (e.g. odourisation).
How does it compare with other systems?
- Pipelines: best for constant consumption, but no flexibility or efficient storage capacity.
- Biogas or hydrogen: emerging alternatives; LNG serves as an energy bridge while these technologies mature.
- CNG (Compressed Natural Gas): useful for short distances/mobile units, but not optimised for mass storage and transport.
Real cases in Spain
In Spain, there are terminals in Barcelona, Huelva, Cartagena, Bilbao, Sagunto and Mugardos, with a capacity of more than 2.3 million m³ and an emission capacity of more than 6.5 million m³/h. These centres have been key in providing:
- Redundancy of supply.
- Third party access to the regulated and flexible market.
Future and trends
- Expansion of floating terminals, quick and less expensive options.
- Development of the virtual pipeline, bringing LNG to remote areas without networks.
- Integration with renewables and hydrogen, to further reduce the carbon footprint.
- Improved efficiency through air vaporisation systems, heat recovery and reduced environmental impact.
Summary Table
| Phase/Element | Key function |
| Reception | Cryogenic unloading from ship |
| Storage | Insulated tanks at -160°C |
| Boil-off/Reliquefier | Control of evaporated gas, reduction of losses |
| Vaporisation | Conversion to gas using seawater or air |
| Measurement & Regulation | Control of flow, pressure and odorant addition |
| Distribution | Pipeline injection or tank transport |
An LNG terminal is much more than a “gas plant”, it is a cornerstone of energy reliability, flexibility and sustainability. Understanding how it works provides insight into why there is currently such heavy investment in this infrastructure as we navigate the transition to cleaner energy sources.