track alternative to shore-based receiving terminals
Italy’s FSRU Toscana project has extended the offshore regasification
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operational throughout. Excelerate went on to install a similar facility, Northeast Gateway, on the US eastern seaboard, off the coast of Massachusetts. But at this point the US shale gas revolution was beginning and the country’s need for gas imports evaporated virtually overnight. Although the US Gateways were little used, Excelerate’s solution was much sought after elsewhere, proving the underlying strength of the floating regas vessel concept.
The configuration that has proved most popular is the company’s GasPort arrangement, in which the regas vessel is berthed at a dedicated jetty, either permanently or for a dedicated import season each year. GasPorts are usually provided with jetty-mounted loading arms for LNG transfers from the delivery tanker.
The next milestone for the Excelerate vessels was the first commercial STS transfer of LNG. This happened in the US Gulf in August 2006 and involved the transshipment of a partial cargo between two of the company’s regas vessels. This was followed in February 2007 by the first commercial transshipment of a full cargo, at Scapa Flow in the UK’s Orkney Islands. The receiving vessel,Excelsior , then proceeded to inaugurate the Teesside GasPort terminal by discharging the first regasified LNG directly into the UK national grid.
In June 2008 the Bahia Blanca GasPort in Argentina received South America’s first LNG cargo. Further GasPorts were commissioned in Kuwait in August 2009 and at Escobar on the Paraná River in Argentina in 2011. Because of the restricted water depth at Escobar, the operation requires STS transfers in the mouth of the nearby River Plate to enable the delivery of part cargoes to the terminal’s regas vessel in conventional size LNG carriers.
The other major players in the regasification vessel sector are Golar and Höegh LNG. Golar made its entry into the field with conversions of its existing ships. Five such conversions have been carried out to date and the company continues to own and operate four of the vessels as jetty-based floating storage and regasification units (FSRUs). Two are working in Brazil, one in Dubai and one in Indonesia. The first conversion, of the 129,000m3, 1981-builtGolar Spirit
by the Keppel yard in Singapore, was completed in June 2008 and enabled Brazil’s first LNG imports.
The fifth Golar FSRU conversion, of the 138,800m3, 2004-built, spherical tank
Golar Frost, was the most ambitious. The ship was sold to the Italian company OLT Toscana and renamedFSRU Toscana. The modification work was undertaken by Drydocks World Dubai and involved the removal of the vessel’s propulsion system and the installation of not only regasification equipment but also a sophisticated turret yoke bow mooring system and deck-mounted loading arms. Designed to remain on station for 20 years, the FSRU marked a further breakthrough for offshore LNG when it went into service at a location off the Tuscany coast in autumn 2013. Golar has extended its commitment to the regas sector through newbuildings. Three such vessels were ordered at Samsung Heavy Industries (SHI) in Korea in recent years. The first of these, the 170,000m3Golar Igloo, has been delivered and has gone into service in Kuwait while the 160,000m3Golar Eskimo is scheduled to
go on station at Aqaba in spring 2015 to enable Jordan to commence LNG imports. The third FSRU newbuilding, the 170,000m3Golar Tundra, is scheduled for late 2015 completion. Golar is providing its newbuildings with regasification equipment capable of processing up to 5.5 million tonnes per annum (mta) of LNG.
Höegh LNG currently has two 145,000m3 regas vessels on charter
to GDF Suez.GDF Suez Cape Ann
is serving as a receiving terminal at Tianjin in China whileGDF Suez
Neptuneis earmarked for a similar, albeit temporary, role at Montevideo for Uruguay’s GNL Sayago project. The vessel will eventually be replaced by a 263,000m3 FSRU that Mitsui OSK Lines
(MOL) currently has under construction at DSME.
Höegh LNG has also been active on the newbuilding front. The shipowner has recently taken delivery of the first two of four 170,000m3
FSRUs contracted at Hyundai Heavy Industries. The pair are being employed under long-term contracts as Indonesia’s second and Lithuania’s first LNG receiving terminal, respectively.
The MOL FSRU will be the largest such vessel when completed in 2016. Another newcomer besides MOL to the regas ship sector is BW Gas. The company has two 170,000m3 vessels
on order at SHI in Korea, the first of which is scheduled to go into service in the Dominican Republic on delivery in 2015. Exmar is building on its expertise in the sector and is promoting its non- propelled, barge-mounted regas floater design. The first such unit is under construction at the Wison yard in China.
Regasification vessels have come a long way in the space of 10 years. As of end-2013 there were 20 regasification projects in service or under construction, and global floating regasification capacity had reached 44.3 mta of LNG, 34 per cent ahead of the previous year, in nine countries. By the end of 2015 a further eight LNG importing nations are expected to have regasification vessel- based terminals in place. MC Excelerate Energy is now carrying out over 100 STS transfers a year in support of its regas vessel operations
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94 ILNG shipping at 50
L
NG carriers have been the last redoubt of the marine steam turbine industry. Until the early years of the new millennium every LNG carrier newbuilding was specified with a steam turbine propulsion system. While all other sectors of commercial shipping had long since been seduced by the greater propulsive efficiencies of diesel engines, LNG owners had stuck with steam turbines for several reasons, most notably their dual-fuel capabilities.Cargo boil-off gas (BOG) generated during the course of an LNG carrier voyage can be burned in a steam vessel’s boilers as readily as fuel oil to generate steam. In addition turbines have proved to be extremely reliable throughout the history of LNG carrier operations. Their low maintenance
requirements are another attribute. Steam turbines are also able to handle any excess cargo boil-off gas by means of dumping surplus steam to the seawater-cooled condenser in the engine room. This capability means that low propulsion system loads pose no undue problems. It also obviates the need for expensive ancillary equipment such as reliquefaction plants and gas combustion units (GCUs).
However, just over a decade ago, on the verge of a major new growth phase for the LNG industry, Gaz de France (now GDF Suez) took the brave step of choosing a new LNGC propulsion system. The LNG industry was pushing to cut costs and improve efficiencies along the transport chain in order to improve the economics of gas projects. Ship propulsion had been identified as an area of potential savings, and investigative work on alternatives to steam turbines on LNG ships had been intensifying.
Through its Gazocéan shipowning subsidiary, Gaz de France ordered the first three LNGCs to be powered by dual-fuel diesel-electric propulsion (DFDE) systems. The newbuilding contract for the 74,130m3GDF Suez Global Energy was placed with Chantiers
de l’Atlantique in February 2002 while orders for two 153,500m3 sisters,Provalys
andGaselys, were placed with the same yard in September 2003 and July 2004, respectively. Complications with the innovative membrane containment system also specified for the three vessels delayed their delivery but they were all in service by March 2007.
Gaz de France was in a good position to pioneer DFDE propulsion because of the company’s control of the supply chains on which the vessels would operate. The three ships loaded cargoes at export plants where GDF Suez had contracted supplies and delivered them to company-owned receiving terminals in France.
Nevertheless, despite the ‘in-house’ nature of the employment, it was still a courageous move for an industry that was notoriously conservative. Gaz de France had been impressed by the performance of Wärtsilä’s 50DF dual-fuel test engine and decided that, given the level of reliability and redundancy provided by the propulsion system, its improved efficiency compared to steam turbines would yield significant cost savings over the life of the vessels.
GDF Suez Global Energy was specified with four six-cylinder Wärtsilä 50DF dual- fuel engines which provide an aggregate power of 22.8MW and a service speed of 17.5 knots. In normal operating conditions natural BOG is complemented, when required, by forced BOG for use as fuel. The engines can run on marine diesel oil in situations where no gas is available.