LNG fundamentals
What is LNG?
Liquefied Natural Gas or LNG is essential for people who are unable to access natural gas via pipelines. LNG is natural gas that has been cooled. When the gas cools, it turns into a clear, colorless liquid. In its liquid state, the LNG cannot ignite. When the LNG reaches its destination, it is safely turned back into gas at regasification terminals. From here, it’s sent along pipes to generate electricity for homes, businesses and industry, while also being used for domestic cooking and, increasingly, transportation.
Natural gas is abundant, reliable and versatile, and LNG is expected to play an increasingly important role in sustaining the world’s energy demands and economic growth. Because natural gas emits significantly fewer pollutants than coal in power generation, it is seen as essential in supporting the energy transition and the drive to Net Zero.
What is the liquefication process?
The liquefaction process plays an important part in making natural gas suitable for efficient, long-distance transport.
The initial steps in this process remove impurities from the natural gas, including liquids and traces of mercury, followed by removing hydrogen sulphide and carbon dioxide in an acid gas removal unit. The gas then goes through various treatment stages, including pre-cooling using a propane refrigerant system and further cooling in the main cryogenic heat exchanger. This process reduces the temperature to around -155°C.
The extreme cooling causes the gas to condense into a liquid state, reducing its volume by about 600 times. As the pressure cools, the LNG reaches a storing temperature of -162°C. The liquefied gas is then stored in specialized cryogenic tanks, each with the capacity to fill a conventional-sized LNG ship. This liquefaction process allows the natural gas to be safely transported.
What is the regasification process?
Regasification happens when the LNG reaches its destination.
Onshore receiving terminals are traditionally used for regasification, as these provide a long-term solution for high-volume needs. These terminals have storage tanks large enough to accommodate the cargo from multiple LNG carriers and are linked to vaporizers that convert the LNG back into a gas state. As a global leader in the Liquefied Natural Gas industry, ExxonMobil is a shareholder in South Hook LNG Terminal Company Ltd., which operates Europe’s largest onshore terminal, in the UK.
We have also worked with our co-venturers to develop the world’s first offshore LNG terminal, which is located off the coast of Italy. Offshore LNG terminals can be particularly useful where there is a limited amount of suitable land. This groundbreaking offshore facility uses an advanced gravity-based structure to store cargo from LNG ships away from communities. The LNG can be regasified offshore before being transported to the mainland via pipeline.
When a fast solution is needed, floating storage units (FSUs) can be installed in under 18 months. These FSUs help provide a versatile and efficient route for LNG offloading, storage and regasification. 2
More LNG questions answered below
The liquefaction process plays an important part in making natural gas suitable for efficient, long-distance transport.
The initial steps in this process remove impurities from the natural gas, including liquids and traces of mercury, followed by removing hydrogen sulphide and carbon dioxide in an acid gas removal unit. The gas then goes through various treatment stages, including pre-cooling using a propane refrigerant system and further cooling in the main cryogenic heat exchanger. This process reduces the temperature to around -155°C.
The extreme cooling causes the gas to condense into a liquid state, reducing its volume by about 600 times. As the pressure cools, the LNG reaches a storing temperature of -162°C. The liquefied gas is then stored in specialized cryogenic tanks, each with the capacity to fill a conventional-sized LNG ship. This liquefaction process allows the natural gas to be safely transported.
Regasification happens when the LNG reaches its destination.
Onshore receiving terminals are traditionally used for regasification, as these provide a long-term solution for high-volume needs. These terminals have storage tanks large enough to accommodate the cargo from multiple LNG carriers and are linked to vaporizers that convert the LNG back into a gas state. As a global leader in the Liquefied Natural Gas industry, ExxonMobil is a shareholder in South Hook LNG Terminal Company Ltd., which operates Europe’s largest onshore terminal, in the UK.
We have also worked with our co-venturers to develop the world’s first offshore LNG terminal, which is located off the coast of Italy. Offshore LNG terminals can be particularly useful where there is a limited amount of suitable land. This groundbreaking offshore facility uses an advanced gravity-based structure to store cargo from LNG ships away from communities. The LNG can be regasified offshore before being transported to the mainland via pipeline.
When a fast solution is needed, floating storage units (FSUs) can be installed in under 18 months. These FSUs help provide a versatile and efficient route for LNG offloading, storage and regasification. 2
Regasification can sometimes take place onboard an LNG ship or barge, and these systems are known as Floating Storage and Regasification Units (FSRUs).
FSRUs can receive LNG directly from LNG ships, storing it in insulated tanks. The FSRU can also regasify the LNG to turn it back into natural gas, ready for distribution to the local grid by pipeline. A flexible solution, FSRUs can be moored quayside, near-shore or offshore, providing single or multiple berth options, and can allow for ship-to-ship transfer so that LNG can go via smaller ships when needed for tight ports or remote locations. They also have the advantage of being quicker to create and cost-effective, as they typically cost under US$300 million to build.
At ExxonMobil, we’ve helped pioneer FSRU technology in the LNG industry, with a history of research, patents and involvement in FSRU projects dating back to the 1990s. These units play an important part in efficiently bringing the benefits of LNG and natural gas to where they’re needed most. 3
LNG is recognized across the world as a cleaner energy source than coal for good reason. It has a significantly lower impact on the environment throughout its lifecycle, emits fewer greenhouse gases and pollutants when burned, and releases lower levels of carbon dioxide, sulphur dioxide and nitrogen oxides during combustion.
The production and transportation of LNG are designed to minimize its environmental impact. Advanced technologies used throughout the LNG value chain help reduce methane emissions. The liquefaction process also allows for the global distribution of cleaner energy through efficient storage and transportation of natural gas over long distances.
LNG offers a cleaner alternative to coal and supports the global transition towards a lower-carbon energy future. At ExxonMobil, we’re committed to advancing technologies and practices that contribute to the cleaner use of natural gas, and LNG has an important role to play in the global energy mix.4
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