Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
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32 Proceedings Fall 2015 www.uscg.mil/proceedings As demand for natural gas grows, natural gas supply solu- tions can be challenging. Building a traditional shore-based gas facility requires a large capital investment and under- going a demanding permitting process. In 2000, industry members explored the concept of foating liquefed natu- ral gas (LNG) regasifcation vessels to satisfy the energy demand. The concept is simple: Create an LNG vessel capa- ble of taking on LNG cargo and delivering it ashore in its gaseous state. Floating Storage Regasifcation Unit The foating storage regasifcation unit, or FSRU, stores liq- uefed natural gas in its cargo containment system, transfers the cargo internally to the vessel's onboard regasifcation plant, vaporizes the LNG to gas vapor, and delivers the gas vapor under high pressure directly from the vessel into the supply pipeline. The vessel Excelsior, built in 2005, is the industry's frst FSRU. Excelsior is capable of delivering high-pressure (HP) gas to a shore-based facility via a submerged turret loading buoy in the bow of the vessel or via an outboard high-pressure gas manifold connection. 1 Since Excelsior's delivery, foating storage regasifcation units have featured varied designs. Some FSRUs are new-built vessels, some are existing lique- fed natural gas carrier conversions. Some use membrane tank cargo containment systems, some use spherical tank designs. Many foating storage regasifcation units can be utilized as traditional LNG carrier vessels when not employed in regas service; some are designed to remain long-term regasifca- tion installations. As of November 2014, the FSRU feet con- sisted of 20 vessels, with a further eight on order. 2 Gas Delivery to Market Two basic types of technologies support FSRUs: • a near-shore or offshore regasifcation terminal, • a deepwater port regasifcation buoy. The near-shore or offshore regasifcation terminal concept is based on a more traditional dockside design. It consists of a central platform area and mooring dolphins that extend out in either direction to permanently moor the FSRU to the jetty. On the jetty platform area, high-pressure gas arms, designed to connect to the foating storage regasifcation unit's dedicated high-pressure gas manifolds, receive the gas from the foating storage regasifcation unit and deliver it directly to the pipeline/shore grid. The deepwater port buoy concept is an offshore buoy- based confguration with a submerged turret loading buoy anchored to the sea foor and a fexible riser that connects to a subsea pipeline. The foating storage regasifcation unit Accessing Landlocked Natural Gas Reserves Floating LNG solutions. by cAPt. stAnlEy WEndElEWski Manager, Marine Operations Excelerate Energy Liquefed Gas Production, Transportation, and Use The FSRU vessel Excelsior. All graphics courtesy of Excelerate Energy.