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