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TRANSCRIPT
Floating SubstationsWhats needed ?Will we ever see floating Substations?
Norwep Seminar Wind Europe 2019
From bottom fixed to floating – how to drive down costs?
27th November
Jan Wigaard, Head of Concept & Studies
Content
• Introduction, will there be traditional Substations in Floating wind ?
• Will there be incremental or disruptive development of Floating Wind ?
• Floater Type selection for Floating HV AC Substation
• How to make a floater unmanned
• HV Equipment for floaters
Incremental development vs Disruptive
Dead
End
Incremental
Disruptive
Will there ever be Floating Substations? Incremental developmentvs Disruptive, and Floating vs Bottom fixed
Dead
End?Incremental
Disruptive
Onshore
Fixed offshore
Floating offshore
Wind Catching SystemProduction and Substation in
one unit (Patented by WCS AS)
Other disruptive
concepts ?
Traditional
Substation
Development in
Electrical export
systems, on a WTG
Floater or Subsea
systems ?
Jackets up to 150 m
water depth?
Traditional SubstationFloating concept selection
• Original Concepts from Oil & Gas
• TLP• stiff tendons to have Heave, Roll and Pitch eigen period below wave energy• 20-25% of bouyancy used for tension
• More costly mooring & Hull
• Benefit for Oil & Gas, less costly steel riser system and dry wellheads, less capex and opex, more production
• Traditional Spar• Deep draught to get below wave action for small heave motion (170m-230m)• Sometimes with damper plates to get more damping if storage not required
• Large and expensive
• Benefit for Oil & Gas, less costly steel riser system and dry wellheads, less capex and opex, more production
• Semi’s• Column/Pontoon Semi Less costly floater and mooring• For Oil and Gas, more expensive flexible risers and subsea wellheads
• For Electric Substations the Pro’s for Spar’s and TLP’s are less important
TLP SPAR
Column &
Pontoon SemiBucket Semi
Study on Floating Substation
• Selection of Floater type
• Develop a layout suitable for the floater
• Sizing
• Marine systems for unmanned operation
• Investigate HV equipment readiness for
Floater motions
• Would it pay of to make a large floater withsmall enough motions to use standard static HV Equipment
Floater concepts evaluated
1. SPAR concepts, advanced SPAR concepts. Not further considered due to
mating at quayside/quayside water depth requirements
2. TLP concept, not further considered due to mooring costs
3. Bucket concept, not further considered due to high construction cost costs,
superfluous storage volumes and expensive mooring system. In Case used
as Oil and Gas FPSO the bucket saves the expensive Oil and Gass turret.
4. Four leg semi with ring pontoon. Concept developed with low motions in
mind.
Develop a layout suitable for a Semi
• Starting point: 800 MW Jacket
topside from a FEED study
• Re-worked the layout to be
suitable for a Semi
• Size the Semi for hars
environment, aim for low
motion
• Mooring system design
• Also considering unmanned
operation design experience
• Execution method and cost
estimate
800 MW AC station
Jacket topside from
a FEED study
Not suitable to place
on a Semi directly
Re-work the
layout to fit with a
Semi
Marine systems for unmanned operation
• Traditional
manned
floater
system
■ Is this your solution?
3000 t
25 m
Pump rooms
A lot of piping with remote
operated valves
Requirements to
access for inspection
and maintenance in
SubstructureConstructed with thin
plates, webframes,
girders and plate
stiffeners, at a
cost/kg as for Semi’s
and ships
Simplified for unmanned operation
3000 t 3000 t
One water pipe
One Submersible
pump
One Pipe/Caisson
for solid ballast
One water pipe to
each column
No equipment to
maintain in
substructure -> no
need for access
Constructed as a
monopile cylinder with
monopile cost/kg
One
compartment
in the ship
collision zone
• Idea first for 1000-2000 t, but
shown feasible for 7500 t. In
principle no weight limit
Simplified Spars may be cost efficient
■ Traditional Spars are constructed more or less as ships, with many tanks/compartments,
access tunnels, stiffened plates and bulkheads, and traditional ballast and bilge systems with
pumps, piping and remote operated valves
■ The simplified Spar is simply a bucket with no internals, some caissons/pipes for temporary
water ballasting and for filling of solid ballast.
Topside layout for unmanned operation with one shortyearly maintenance campaign
• Plan as unmanned, find alternative methods, not just instrument and automate existing
designs
Sizing Challenge for smaller Topsides
• Aibel Damped Wind Floater, introduction of mechanicaldamping to add to hydrodynamic damping• The Idea is to avoid the sizing large critiera
3000
t
Traditional 4 Column/Pontoon Semi’s
need a certain size
Floating Wind Turbine
inspired Floaters may be
more suitable for the
smallest Substations
Motions and HV Equipment• Typical motions for Semi’s and Spars, Horizontal acceleration also similar for TLP’s
• Static situation ( mean tilt in waves and wind):• Inclination +-1degrees
• Bad weather, Ultimate Limit state harsh environment• No damage normal operation requirement• +-7 degrees dynamic inclination, Period 10-15 seconds• 3m/s2 accelerations in any direction (effect of g*sin(tilt) included, not to be added)
• Accidental case, survival, not in operation, no requirement to be operable after incident, but shall not lead to a progressive incident• 17 degrees inclination in addition to +-7 degrees from wave loading, may be less, 17 degrees is requirement to stay
below in a damage compartment case from Norwegian Maritime Directorate
Special for GIS:
• The Floor deflection will on a floater also be dynamic, will have a mean value from static weight, and a +- value from the vertical acceleration and deflections due to direct wave loading, may lead to issues of Gas tightness.
• HV Equipment Readiness• Believed to be a matter of minor design updates and a process of type approval• But no HV Equipment supplier has yet confirmed to Aibel that such equipment is available today for the
motions as given herein.• AC development just starting, DC will follow but take even longer
Mooring system research
• Norwegian Research Council sponsored
• Innovative Mooring systems for Floating Wind, Aibel partner
• Fibre Rope Mooring innovations, Aibel project owner• Innovative park layouts
• Wave frequency Load reduction elements
• New Fiber technologies
Commercializing Floating Wind
Whats needed for floating wind in general and Substations?
• For Turbine Foundations• Fabrication capacity and capability needs to be established• Assembly line and mass-production, the car industry is not
necessarily comparable
• Assembly at quayside or offshore – lifting capacity when turbine sizes increases
• Cost Efficient low motion small size unmanned Floater design
• Substation layout fit to a particular floater
• Dynamic cables, • 220 kV AC and 320-525 kV DC for Substation export Cables
• Innovative mooring systems
• Floating substations• Not cost effective to make a Floater large enough for static HV
equipment
• Simplified ballast system
• Unmanned philosophies
• Build on lean design basis from AC Substation FEED
• Main HV Equipment not available yet for Floaters!
Assembly as done for
Hywind Scotland
Possible new yard set up for 50 Floating
Turbines
Substructure Fabrication line
and turbine assembly
Aibel Floating Substation