a floating multi turbines platform - sintefwindsea as, january 2012 marc lefranc a floating multi...

WindSea AS, January 2012 MARC LEFRANC

A floating multi‐turbines

platform

The Company

• Norwegian company based in Sandvika

• Established in 2008

• Fixed and floating foundations for offshore wind

• Owned by NLI and FORCE Technology

1

•Norwegian company

•Engineering, fabrication, and

technology

•Offshore oil & gas, and hydropower

•2000 employees

•50% owner in WindSea

•Norwegian/Danish company

•Engineering, material technology

and Inspection

•Offshore oil & gas, and wind power

•1200 employees

•50% owner in WindSea

WindSea’s solutions

2

Floating platform

Fixed jacket structure

Semi-submersible platform

Applicable from 45 meters to very deep water

Carries three full size (5MW+) turbines

Some R&D work still needed

Simple jacket structure

Applicable from 20-50 meters

Cost effective fabrication and installation

Concept is ready for commercial projects

0-10

10 -20

20-30

30-40

40-50

50-60

60-70

> 100

Wa

ter

de

pth

in

me

ters

- 1 000 2 000 3 000 4 000 5 000 6 000 7 000

0-10

10 -20

20-30

30-40

40-50

50-60

60-70

> 100

Wa

ter

de

pth

in

me

ters

Round 1

Round 2

Round 3

3

The market for the WindSea’s foundations

Largest growth in water depth > 30m Water depth for use of technology

Potential installed capacity (MW)

Gra

vit

y b

ase

Tri

po

d

Mo

no

pile

Jacket Floating concepts

Source: Crown Estate 2009, edp (The WindFloat Project, May 2010) and WindSea

Fixed substructures

Sem

i su

bm

ers

ible

Sp

ar

bu

oy

WindSea

concepts

WindSea’s jacket concept - cost effective fabrication,

transport and installation

4

The WindSea jacket Key facts

Design Vertical legs

Modular design

Piling through legs

Turbines All commercial offshore

turbines

Water depth: 20-50 meters

Access

system

Effective and secure boat

landing and staircase system

Status

Concept ready for commercial

use

•Semi-submersible

platform

• Three columns

•Three turbines

• Mooring system

connected by

a ”turret”.

•Self orientation

against the wind

• Inclined towers

WindSea Floater: Key Facts

Key Facts

• Build complete platform at yard

• Tow with commissioned turbines

• Pre-installed anchor system

• Platform self oriented to the wind

• Easy connection to mooring system

• Optimum power production

• Based on proven technology

•Easy access by helicopter or boat

•Large deck area: allow for maintenance

•May be easily towed back to yard for major repair and

inspection

6

Wake Effect / Turbulence

7

Wake Effect / Turbulence

•Reduction of power production at the

rear turbine

•No turbulence effect from the up wind

turbines on the rear turbine

•Inclined towers result in less interaction

with the rotor blades

8

Power production

Based on a specific field

data, a specific turbine type.

•Total power production of 3

standing alone turbines:

• 44,5 GWh/year

Rear turbine power

reduction: 25 %

•Total power production for

Windsea: 41,4 GWh/year

• 93% of the theoretical

9

Power production versus wind velocity

0

0,5

1

1,5

2

2,5

3

3,5

4

5 10 15 20 25

Wind velocity (m/sec)

Po

we

r (M

Wa

tt)

No wake losse With wake losses

Production versus wind velocity

0

1000

2000

3000

4000

5000

6000

7000

5 7 9 11 13 15 17 19 21 23 25 27

Velocity (m/sec)

Pro

du

cti

on

(K

Wh

/y

ea

r)

Model Test: Validation of the concept

•Validate the main principles of

the concept and prove its

physical feasibility.

•Verify interaction between

turbines.

•Verify effect of turbines on

vessel motion.

•Verify effect of vessel motion

on power production.

•Verify the self-orientation

property.

10

Model Test: Wind Tunnel

• Aerodynamic interaction in-between the turbines. Scale 1:150

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Model Test: Wind Tunnel

•One wind velocity, 5 directions

•The power of the aft turbine

was reduced to 89% of the

average of port and starboard

turbine power.

•The forward turbines were only

marginally affected by one

another or by the aft turbine.

12

7

7,2

7,4

7,6

7,8

8

8,2

8,4

-15 -10 -5 0 5 10 15

Ou

tp

ut

Angle of incidence

Power output

Port Turbine Aft Turbine Starboard turbine

Model Test: Wave Basin

• Interaction between Wave and wind induced motion. Scale 1:64

13

Model Test: Wave Basin

14

Maximum Motion

Hs Heave Pitch

Without turbine With turbine Without turbine With turbine

2,5 m 0,4 m 0,3 m 0,6° 1°

5,5 m 1,8m 1,6 m 2,2° 3,1°

13,8 m 8,5 m 8,7 m 1,8° 3,4°

Standard deviation

Hs Heave Pitch

Without turbine With turbine Without turbine With turbine

2,5 m 0,1 m 0,08 m 0,17° 0,2°

5,5 m 0,4m 0,38 m 0,38° 0,75° *

13,8 m 2,5 m 2,5 m 0,74° 0,76°

* This high value is due to operational problems during the test. A more refined analysis of the time history is required. Value around 0,3 is most likely.

Model Test: Wave Basin

15

Power production

Hs Turbine 1 Turbine 2 Aft Turbine

0 m 3,0 3,0 1,4

2,5 m 3,0 3,0 1,2

5,5 m 3,1 3,3 1,4

13,8 m 3,5 3,0 1,3

Model Test: Conclusions

• Results in accordance with calculations

• No interaction between the two up-wind turbines

• Reduction of power production for the rear turbine

• Heave motion identical for both conditions: with and

without turbines

• Pitch motion slightly increased when turbines are in

action (Hs 5,5 m; 2,2˚ to 3,1˚)

• Power production almost independent of the sea

state

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CONCLUSION

• WindSea Concept has been proven to be

feasible.

• WindSea has a wide range of application area.

• WindSea reduces the cost of installation.

• WindSea reduces the maintenance cost.

• Economic analysis shows that the cost per MW

is at lower bound of today’s solutions.

• Further optimisation / tests will bring the cost

lower.

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Thank You for Your attention

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