TEMA LNG-FSRU PROJECT
Demand for Gas in Ghana
The demand for Gas in Ghana has been driven by the needs of Power Generation
Companies which culminated in the construction of the West Africa Gas Pipeline.
The discovery of Gas in the Jubilee Fields was expected to plug the national
supply deficit hole.
The contrary has been true as the country’s demand in the next decade will far out
strip supply from both the West Africa Gas Pipe Line and Jubilee Fields at full
Table 1 below shows national demand of Gas for power generation and table 2 shows
Table 1 Source VRA
Table 1 Source VRA 210
GAS DEMAND FOR NON-POWER COMPANIES
Table 2 Source VRA
The Project involves the deployment of a Floating Storage Regasification Unit
( FSRU) off the Port of Tema to supply LNG to feed power plants and industry
in the Tema Area
The project is being undertaken by a diverse and experienced group including:
§ HML Marine Power & Energy Ltd
Key Beneﬁts of an FSRU
§ FSRU is a more cost-effective way to meet low demand or to “grow into”
LNG than traditional land based terminals
§ Flexible location selection
§ Can be relocated
§ Quicker to develop than land-based facilities
§ Cost competitive with land-based facilities
§ Suitable for location offshore
§ Improved navigational safety as LNG carriers stay offshore
§ Side-by-side ofﬂoading
Floating Storage and Regasification Unit (FSRU) is based on conversion of an existing
LNG carrier. The FSRU is to be permanently moored offshore and export gas to shore
through a sub sea pipeline.
The vessel is permanently moored to the seabed with a turret mooring arrangement, and
the gas send-out line is arranged through the turret down to the seabed and to shore via
a seabed pipeline. The LNG tankers offloading to the floating terminal will be moored in a
side-by side configuration.
LNG is sent from the tanks to the regasification skid situated forward. The regasification
skid essentially comprises booster pumps and steam heated vaporizers. The booster
pumps will increase the pressure to about 90 bar, before the high pressure LNG is
vaporized, after which the gas passes through a fiscal metering unit and is sent to the
sub sea pipeline via the gas swivel and flexible risers.
Turret Mooring Systems
Source: Golar LNG
Turret Mooring Systems
The internal turret mooring system is Bluewater’s
most frequently supplied turret mooring system. It
can be used in medium and deep water
applications. This type of mooring system is
widely used on FPSOs, FSOs and FSRUs. Its
design has been proven time and time again in
the harshest North Sea conditions.
§ Turret and spider
§ Anchor arrangement
§ Product transfer system
§ Turret casing
Turret and Turret Casing
The mooring system consists of a (geo)static
part, connected to the seabed, called the
“turret” and a rotating part, integrated within the
FSRU hull, called the “turret casing”.
These two parts are connected via a bearing
arrangement. This bearing arrangement allows
the rotating and geostatic part of the system to
rotate, thus allowing the FSRU to freely
weathervane around the turret to a stable
position such that the loads on the FSRU are Source: Bluewater
An anchor arrangement is applied to connect the FSRU to the seabed.
Dynamic behaviour calculations are made for each internal turret mooring
system to predict the behaviour of the FSRU for various wind, wave, and
current conditions. These calculations determine the optimal anchor leg
arrangement, and the size of the various anchor leg components.
Soil data at the site location will be examined, by Bluewater Geotechnical
Engineers to determine type and size of anchors.
Basic anchor leg components are:
Anchors or piles, depending on the soil data, to connect the anchor legs to
Anchor line (chain, steel wire, polyester rope or combination of these)
Chain stoppers to connect the chain to the spider
Product Transfer System
The heart of each turret mooring system is the product transfer system.
From or to a geostatic location, e.g. a Pipe Line End Manifold (PLEM), riser
base which is fixed to the seabed, this system transfers product to the
FSRU, weather vanning around the turret.
The basic product transfer system components are:
Flexible subsea hoses, generally referred to as “Risers”
On board process piping
The risers connect the subsea piping to the FSRU. These risers are
flexible hoses coming from the seabed or from a nearby loading tanker.
The configuration of these risers can vary, depending on water-depth, sea
state, FSRU motions, etc.
Bluewater Engineers thoroughly determine FSRU motions caused by
weather conditions, sea state and water depth in computer models in order
to predict the dynamic behaviour of the risers and determine the optimal
The design of the turret mooring system allows for the connection of over
50 risers and associated umbilicals, providing paths for gas and water as
well as the associated paths for hydraulics, chemical injection, power,
control and optical signals.
Since turret-mooring systems usually accommodate a large number of
paths, these systems are equipped with a swivel stack rather than a single
product swivel. This swivel stack is the connection between the geostatic
risers and the FSRUs piping and is located above the turntable.
Side by Side Loading
GOLAR LNG & Bluewater
Golar is one of the world’s largest independent owners of LNG carriers.
Sonangol Gas will supply the LNG to the FSRU
Financial & Transaction Advisors
Mooring and O&M
Bluewater is a leading technological company specializing in the design
development lease and operation of Tanker Based Storage Systems and a
leading provider of Mooring Technology.
Bluewater will be responsible for the mooring, operation and management
of the FSRU
HML Marine Energy & Power Ltd
HML is a consultancy company providing a one stop solution to the oil gas
and power sectors in West Africa
Bluewater have been designing, installing and operating Turret Mooring Systems
since 1993. Many of the world’s leading Operators employ Bluewater’s turret and
swivel technology in their assets around the world, including the North Sea, Far
East, South Africa and Brazil. Applications and operating challenges are broad
and diverse, with water depths ranging from 70m to over 1000m and tankers from
26,000 to 280,000 (DWT).
While each of Bluewater’s turret systems is individually adapted and tailored to
specific project requirements. All Bluewater Turret Mooring systems incorporate
innovative design, investment in research, development and years of operational
feedback resulting in:
§ Low maintenance and high reliability
§ Safety and integrity of a passive design
§ Ease of accessibility
§ Designs that minimize loss of storage capacity but retain riser capacity
§ Structural designs focused on reduced fatigue and wear
§ Continuous improvement through the operational feedback and lessons
learned from Bluewater operated FPSO turrets
HML Marine Energy & Power Ltd