Technological differentiation as SENER’s strategic advantage - June 2014 - Number 47 /Up-to-Date
Floating storage regasification units (FSRU) are a flexible and adaptable solution to the growing worldwide demand for gas. These mobile plants have the capability to supply a market that demands gas as a primary power source in locations where it is oftentimes not possible to install an on shore regasification plant.
SENER was able to develop this solution because of its extensive experience in marine design, on-shore regasification terminals, marine civil engineering (including off shore platforms) and combined cycle power plants: a comprehensive set of skills with a scope shared by few companies in the world. SENER has employed this know-how to design various FSRU configurations: off shore/ island jetties, close to shore/jetties, and off shore/turret moored units.
These off shore units are very flexible and adaptable to different needs. They have an output capacity of 0.2 to 5 billion m3 (BCMA) per year, storage capacity ranging from 20,000 m3 to 200,000 m3, and output pressures from 25 to 100 bar.
FSRUs make it possible for gas-importing countries to diversify their gas sources, which can be crucial for staying energy-independent. Moreover, these types of modular floating units radically shorten installation times, making them a fast solution for increases in demand in geographic areas that do not have their own regasification infrastructure.
Depending on the geographical needs in each case, SENER offers three main configurations:
Off shore/island jetty: in this configuration, the FSRU is located on the sea, away from the coast, but is easily accessible: permanently moored to a dual berth island jetty and able to receive liquefied natural gas (LNG) carriers ranging from 240 to 315 m long (with capacities of up to 217,000 m3 and 12 m draft). The FSRU is a steel non-propelled double hull vessel. Underwater pipes bring the natural gas to a series of receiving facilities on the coast called ORFs (On shore Receiving Facilities). The tanks can be isolated using non-integrated independent SPB (Surge Protection Barriers)-type tanks, or using either membrane technology (with central longitudinal bulkhead separating the two rows of tanks in order to prevent sloshing related problems). The unit can hold a staff of 45 persons, including the regasification plant operators and the ship’s crew.
Close to shore/jetty: this configuration is used in sheltered waters protected by the coast and with the FSRU permanently moored to a dual berth island jetty. It is similar to the preceding configuration, except instead of the underwater pipes it uses an access platform to bring the natural gas to the ORF. Furthermore, unlike the previous configuration, the membrane tanks do not have a longitudinal bulkhead, since there are no sloshing problems due to the waters being on the coast. Therefore, the structure is lighter. The unit can hold a staff of 15 persons.
Off shore / turret moored: the FSRU is permanently docked using a turret system and an anchor field at the bow. The LNG is transferred from the tankers in a side-by-side configuration with ship-to-ship systems. As in the case of the previous systems, the FSRU is made with steel double hulls. It is equipped with independent non-integrated SPBs that make it possible to supply gas for 30 days when operating with the natural gas dispatch in the design. Gas is sent to the coast with a riser using a tower located at the bow and an underwater gas pipeline. The unit has an extensive processing facility area and space for a crew of 45 persons.
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