The FSRU Concept
The FSRU is the floating offshore equivalent of the onshore LNG receiving terminal. As the unit is located offshore or inshore, the LNG can be supplied directly to the unit by conventional LNG carriers. The LNG carriers do not need to enter a port, and the location of the FSRU can be optimized with respect to the gas grid interconnection point, while staying far away from inhabited areas. Onerous site selection issues common to the onshore receiving terminal are thus avoided.
New-Built FSRU Concept
SBM's FSRU concept can be designed for a wide range of conditions. The generic design developed by SBM to pre-FEED level has a typical LNG storage capacity of 300,000 m³ and gas send-out capacity of 1,000 MMscfd at a pressure up to approx. 100 barg (1,400 psig). This design allows for either side-by-side or tandem offloading of the imported LNG. The FSRU is moored to the seabed in relatively shallow water depths via a turret mooring system and can withstand the severest (100-year return period) hurricane conditions as predicted for the Gulf of Mexico.
Main advantages are:
- Key enabler to gas imports in areas where onshore developments are restricted
- Cost-efficient alternative to onshore terminals for sub - optimal site conditions
- Can be located in many parts of the world
- Possibility of leasing and relocation
- Easy permitting / No land acquisition
- Ensure Homeland security
- Enhanced navigational safety
- Out of sight location possible
- Known side-by-side loading operations
- Field-proven components
Converted FSRU Concept
The conversion FSRU is specifically attractive in situations that require a short-term gas supply solution at relatively low cost, or to supply gas to isolated gas consumers.
For typical gas send-out below 500 mmscfd, SBM can offer an FSRU based on the conversion of an existing LNG carrier for a maximum storage capacity of approximately 140,000 m3.
Membrane type (for benign environment) or MOSS type carriers (for more exposed locations) can be employed. LNG offloading is primarily performed in a so-called "side-by-side" arrangement. The converted FSRU is typically equipped with an external turret mooring system, but other mooring options are also possible.
The Converted FSRU has all the advantages of the New-Built FSRU plus:
- Significant cost saving compared to onshore terminals in all cases
- Unbeatable delivery schedule (less than 2 years)
The FRU Concept
The FRU is also a floating LNG receiving terminal, but instead of storing the received LNG in cryogenic storage tanks in the vessel, the gas is instantly vaporized at a high rate, and is subsequently stored in subterranean reservoirs (in so-called 'salt-caverns') as a high-pressure gas at ambient temperature. This concept enables very high peak send-out rates combined with large storage capacity.
The FRU is very suitable for supplying large quantities of gas into a large pipeline distribution network, as they exist in the USA or in Europe. The large gas-cavern storage volume also enables the unit to function as a peak-shaving facility.
The FRUconcept is based on the conversion of a Suezmax crude oil carrier, which is modified to provide a platform for the regasification process and to enable mooring and LNG offloading from the LNG carriers.
The FRU is equipped with an external or internal turret mooring system, but also other mooring methods are feasible depending on the environmental conditions.
The FRU has no or limited LNG storage, as the LNG received from the carrier is instantly vaporized and transferred to the salt-cavern underneath the sea bottom at similar LNG offloading rates as used on onshore terminals and at high pressure (typically up to 150 barg/2,000 psig).
From the gas cavern storage, gas can be delivered into the gas grid at high peak rates, up to e.g. 3BCF/day. The continuous send-out would be somewhat lower, i.e. 1.5 - 2 BCF/day.