Photo: Dr. Jean-Paul Rodrigue, 2006.
There has been a growth in the consumption of natural gas in the global economy, particularly for power generation. Natural gas is one of the cleanest and most energy-efficient fossil fuels and has a composition of about 95% methane. As the demand for natural gas increases, so does the need for its transport. While the great majority of natural gas is shipped through pipelines, additional demands in Japan, Western Europe, and the United States required the construction of specialized natural gas carriers to carry this commodity over very long distances. Liquefied natural gas (LNG) is a liquid form of natural gas that is much easier to transport. Through a cryogenic process where the temperature is brought down to -163 degrees Celsius (-256 degrees Fahrenheit), natural gas loses 610 times its volume under normal atmospheric pressure. Thus, significant quantities of natural gas can be transported. However, establishing a distribution system for LNG is complex and costly. It involves extraction, liquefaction, shipping, storage, and re-gasification. Additionally, since storage systems are not perfect; about 5% of the LNG can be lost for a 3 weeks journey as it reverts back to its gaseous form by boiling. LNG carriers are designed to use this boil as fuel for their engines.
The ship on the above photo, the Castillo de Villalba (delivered in 2003), uses a membrane containment system with a capacity of around 138,000 cubic meters. South Korea accounts for 70% of LNG ship production with builders including Daewoo Shipbuilding and Marine Engineering (the World’s largest), Hyundai Heavy Industry, and Samsung Heavy Industries. Construction costs are very high; $200 million for a 200,000 cubic meter ship. As of 2011, 359 LNG carriers were in operation, a sharp increase since as of 2005 the global fleet was around 182 LNG carriers.