offshore wind power and the challenges of large-scale

Offshore Wind Power and the Challenges of Large Scale Deployment

Walt Musial

Manager Offshore Wind and Ocean Power Systems

National Renewable Energy Laboratory

Inaugural Meeting of the North American Wind Energy Academy August 7th - 9th, 2012 Photo: Baltic I – Wind Plant

Germany 2010 Credit: Fort Felker University of Massachusetts Amherst

William E. Heronemus University of Massachusetts

Circa 1973

UMass has Pioneered Offshore Wind Energy

Alpha Ventus – RePower 5-MW Turbine

Siemens 2.0 MW Turbines Middlegrunden, DK

Vestas 2.0 MW Turbine Horns Rev, DK

• 51 projects, 3,620 MW installed (end of 2011)

• 49 in shallow water <30m

• 2-5 MW upwind rotor configuration (3.8 MW ave)

• 80+ meter towers on monopoles

• Modular geared drivetrains

• Marine technologies for at sea operation.

• Submarine cable technology

• Oil and gas experience essential

• Capacity Factors 40% or more

• Higher Cost and O&M have contributed to project risk.

Offshore Wind Power 3 National Renewable Energy Laboratory

Offshore Wind Projects Cumulative And Annual Installation;

The U.K. And Denmark Account For Nearly 75% Of Capacity

‐

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

‐

200

400

600

800

1,000

1,200

1,400

1,600

Cumulative Installed Ca

pacity

(MW)

Annu

al In

stalled Ca

pacity

(MW)

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011


30

25

Offshore Wind Projects Installed, Under Construction, and Approved

Capa

city

(GW)

20

15

10

5

0

3,620 MW 3,500 MW

25,585 MW

Installed Under Construction Approved

Offshore Wind Turbine Market Is Becoming Increasingly Diversified

Fuji Heavy Shanghai Electric GE Enercon Areva

Siemens 44%

Vestas 10% Repower

6%

Sinovel 5%

Areva 15%

BARD 11%

Goldwind 2%

Iberdrola 3%

China Energine 3%

1%

Mingyang 0%

Siemens 48%

Vestas 39%

Repower 6%

vel %

WinWind 2%

1% 1% 0% BARD 0%

0%

Nordex 0%

Goldwind 0%

Installed Capacity ~3,620 MW

Projected Near-Term Capacity*

* Includes projects under construction and approved projects that have announced a turbine manufacturer 6

Installed capital costs have increased substantially from 2005 levels

Weighted-average cost of planned offshore wind projects = $4,862/kW

Offshore Wind Cost of Energy Reduction Scale of Global Deployment • Learning Curve • Volume Production • Supply Chain Maturity • Deployment and Field

Experience

Risk Reduction • Permitting • Construction Delays • Ops – Reliability & Production • Financial and Market

Uncertainty

Technology Innovation • Turbine Optimization • Balance of Station • Offshore Grid • Array optimization • Integration

Mature Market Cost

Scale

Risk

Technology

Time

Initial Cost

Present Year

Installed capital costs for offshore wind turbines Turbines account for only 32% of ICC

9

Larger scale is needed to achieve lower offshore wind cost

Larger Turbine Sizes Large Scale

Increased Wind Deployment Plant Sizes

National deployment targets in the E.U., U.S., and China call

for ~86 GW of offshore wind to be installed by 2020 Ca

pacity

(MW)

100

90

80

70

60

50

40

30

20

10

0 0.1 0.1 0.2 0.2 0.3 0.3 0.5 0.6 0.7

3.0 1.3

30.0 86.3 China

USA

10.0 EU 18.0 46.3

10.0

6.0

5.2


Offshore Wind Technology is Depth Dependent


‐10

0

hi

Near-term offshore wind projects will be installed in deeper waters and further from shore

0

10

20

30

40

50

60

20 40 60 80 100 120

Dep

th (m

)

Distance to Shore (km)

200

210

220

Shallow Water

Transitional Water

Deep Water

Installed Project

Under Construction

Approved Project

Bubble size represents project capacity

Near-shore Far-shore (DC power export technology becomes competitive)


‐10

0

hi


0

10

20

30

40

50

60

20 40 60 80 100 120

Dep

th (m

)


200

210

220

Shallow Water

Transitional Water

Deep Water

Installed Project

Under Construction

Approved Project




‐10

0

hi


0

10

20

30

40

50

60

20 40 60 80 100 120

Dep

th (m

)


200

210

220

Shallow Water

Transitional Water

Deep Water

Installed Project

Under Construction

Approved Project



Cape Wind


‐10

0

hi


0

10

20

30

40

50

60

20 40 60 80 100 120

Dep

th (m

)


200

210

220 Floating Technology Demonstration Projects

Shallow Water

Transitional Water

Deep Water

Installed Project

Under Construction

Approved Project



Cape Wind


Common Foundation Types Used in Shallow Water (0-30m depths)

Monopiles Gravity Base 73% of Current Installations 21% of Current Installations


Cape Wind 468-MW Wind Plant - Massachusetts

Location: Nantucket Sound, MA

Turbine Size/Description: 130 Siemens 3.6 MW wind turbines

Expected Deployment 2013 Date : Foundation Type: Monopiles

Average distance from 9.5 miles shore Average Water Depth 11-m

Expected Energy 1.5 Billion KWh/yr production Approximate Budget: $ 2.6 B USD

The Cape Wind project is the first and only offshore wind project to receive a license to begin construction in U.S. federal waters The project will produce 75%

of the electricity for Cape Cod and the Islands.

Transitional Water Depths Need Multi-pile Support Structures (30-60m)

Tripod Type Jacket or Truss Type


Multi-pile foundation designs are gaining market share as larger turbines are installed in deeper water

72.7%

20.9%

5.3% 1.0%

0.1%

58.0%

12.8%

28.9%

0.3%

Projected Near-Term Capacity*

~10,070 MW

Installed Capacity ~3,620 MW

Gravity bases are not represented in the near-term plans of developers

* Includes projects under construction and approved projects that have announced a foundation design 20

Turbine Scaling Trend Based on Current Installations: Generator size, rotor diameter, and hub height are increasing 10.0 130

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0.5 0.5 0.5 0.6 0.6 2.0 1.9 2.0 2.2 2.5 3.0 3.0 3.0 3.2 2.8 3.1 3.9 3.9 4.1 4.2 4.9

Weighted Average Capacity (right axis)

Individual Project Capacity (left axis)

Weighted Average Rotor Diameter (right axis)

Weighted Average Hub Height (right axis)

0.0 (10) 1990 1995 2000 2005 2010 2015

9.0

Rotor D

iameter

and

Hub

Height (m)

110

90

70

50

30

10

Rated Ca

pacity

(MW)


Offshore Turbines Sizes are Expected To Continue To Grow

Source : Jos Beurskens - ECN Netherlands Offshore Wind Power 22 National Renewable Energy Laboratory

Large Offshore Turbine Technology (5-10 MW)

Challenges • Mass scaling laws limit conventional designs • Installation vessel capacity limits design

options • Composite technology for large machines is

unproven

Enabling technologies for large machines • Ultra-long blades/rotors • Downwind rotors • Direct drive-generators (possible HTSC) • High reliability integrated systems • Innovative deployment systems • Special purpose vessels


Blade Scaling Critical for Large Turbines The need for larger blades is driving advanced material,

manufacturing, and design innovations

Commercial Wind Turbine Blade Weights

App

rox

Bla

de W

eigh

t (kg

) 50,000

40,000

30,000

20,000

10,000

0

Historic trend O

fOy = 1.5336x2.3183

ffshore Blades

fsho

Onshore

re Blades

Quadratic Scaling Can this be achieved?

Blades

0 20 40 60 80 100 Blade Length (meters)


Offshore Trend Toward Direct Drive Generators

Goldwind

Graphic: Courtesy of American Superconductor

Siemens Wind Power

• Conventional gear driven turbines offered lightest and lowest cost but have had suffered high maintenance costs

• Direct drive generators (DDG) promise higher reliability due to fewer moving parts

• New designs promise lighter weight

• Most OEMs are developing 5-7MW class DDGs wind turbine (or medium speed)


Electric Grid and System Integration

Challenges • 54-GW by 2030 of Offshore Wind • Constrained land-based grid in high

population density coastal regions • Variable power delivery and

establishing capacity value • Up to 80% of Offshore Insurance claims New Offshore Grid Technologies • Offshore backbones for power delivery • HVDC for long distance power • Aggregate offshore wind plants • Cable protocols

HVDC Power Networks Credit: KEMA

Baltic 1 Substation

Proposed Super-grid for European Offshore Wind


Offshore Metocean Characterization Tools Challenges • High cost of MET masts has inhibited

widespread metocean characterization • Marine boundary layer (wind shear,

stability, and turbulence) is not well characterized

• Resource assessments rely on sparse measurements for validation

• External design conditions for turbines Floating wind LIDAR; The Natural Power Sea are not well understood

New Technology for Metocean Characterization:

• Remote sensing (LIDAR, SODAR) • Measurement campaigns for

metocean conditions at hub height • Improved weather models • Integration of multiple data sources for

validation (e.g. satellites, met towers) • Improved forecasting

ZephIR (from http://blog.lidarnews.com)


OFFSHORE WIND ARRAY EFFECTS


Offshore Wind Turbines in Atlantic and GOM Must be Designed for Hurricanes

• Wind Turbines are often Type Certified before site conditions are known

• High uncertainty in predicting hurricane probability and intensity

• U.S. Hurricane conditions can exceed IEC Class 1A wind specifications

• New Standards and Protocols will address Hurricane Design

Typical characteristics of hurricanes by category Scale Number Winds

(Category) (Mph) (Millibars) (Inches) Surge (Feet) Damage

1 74-95 > 979 > 28.91 4 to 5 Minimal

2 96-110 965-979 28.50-28.91 6 to 8 Moderate

3 111-130 945-964 27.91-28.47 9 to 12 Extensive

4 131-155 920-944 27.17-27.88 13 to 18 Extreme

5 > 155 < 920 < 27.17 > 18 Catastrophic

Table 1. Saffir/Simpson Hurricane Scale, modifed from Simpson (1974).


Breaking Waves: A potential design driver

• Breaking waves can occur when wave height approaches water depth (critical at some locations)

• Design must consider occurrence during extreme 50/100 year return storms

IEC 61400-3 Breaking

Wave Model is not

validated

• Breaking waves can double the load magnitude

• Validation data is needed to improve and validate the model.

b = maximum elevation of the free water surface R = radius of the cylinder = curling factor 0,5

where: C = wave celerity Hb = wave height at the breaking location


Ice Loading Design and Mitigation

Ice Force •Thickness •Strength •Velocity •Fracture Mode

Induced Mechanical Vibration Resonant Frequency Shift

Excitation Lock-in

Base Load Force

Baltic Sea – Windpower Monthly Cover Photo Feb 2003

Wind Turbines at Nysted with Ice Cones


SPAR BARGE TENSION LEG

PLATFORM


Floating Offshore Wind Turbines

Graphic: Glosten Photo: Principle Photo: Hywind/Statoil Associates, PELESTAR Power Inc. SPAR TLP SEMI-SUBMERSIBLE

Summary of Challenges and Opportunities

• Initial costs are high due to smaller scales, higher risk, and immature technology

• Global scale deployment is needed for cost reduction

• Stable policy incentives are needed to offset first adopter cost challenges

• Technology innovations are needed to lower cost and expand siting options

• Unique environmental conditions require optimized turbine designs

• Mature costs realized through scale and innovation.

offshore wind power and the challenges of large-scale

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