Nick Baldock Garrad Hassan and Partners Ltd

Quantifying risk through a rigorous analytical approach to the real world challenge of offshore wind construction – downtime, constraints and

sequencing.

Nick BaldockGarrad Hassan and Partners Ltd

Contents

Problems Facing Offshore Wind Farm

Construction

Garrad Hassan Approach

Validation Case Study

Conclusions

Summary

Contractual interface

risks

Few EPC offerings

Complex&

costly

Marginal economics

Risk

Offshore Wind Farm Construction

Offshore Wind Farm Construction

Time & Budget Contingency

Optimal Vessel Strategies

Supply Chain Risks

Assessing Weather Delay

Capturing Project

Restrictions

Managing Contractors

Questions?


O2C (Optimise Offshore Construction) Model - Structure

DEFINEOPERATIONS

LONG-TERMWEATHER DATA

TIME DOMAINSIMULATIONS

OPERATION DURATION

DISTRIBUTIONS

DEFINESEQUENCE RULES

DEFINE PROJECT

DEFINE OTHER CONSTRAINTS

DEFINE BUILDSEQUENCE

MONTE CARLO ENGINE

PERTURBSEQUENCE

OPTIMAL SEQUENCE

TOTALDURATION

DISTRIBUTION

STAGE 1

STAGE 2

Stage 1 – Time Domain Simulations

- Operation Duration Distribution

- For each defined offshore operation

- Monthly basis

DEFINEOPERATIONS



OPERATION DURATION

DISTRIBUTIONS

Monopile & Transition Piece Installation

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 200 400 600 800 1000 1200

Operation Duration [hrs]

Itera

tions

Ideal Duration 50hrs


O2C (Optimise Offshore Construction) Model - Structure

DEFINEOPERATIONS



OPERATION DURATION

DISTRIBUTIONS


DEFINE PROJECT



MONTE CARLO ENGINE

PERTURBSEQUENCE

OPTIMAL SEQUENCE

TOTALDURATION

DISTRIBUTION

STAGE 1

STAGE 2

0

500

1000

1500

2000

2500

0 50 100 150 200 250 300 350 400 450 500

Project Duration

No.

Ite

ratio

ns

- Project Build Duration Distribution

- For each defined activity sequence

• Weather Downtime

• Logistical Downtime

Stage 2 – Programme Modelling & Optimisation


DEFINE PROJECT



MONTE CARLO ENGINE

PERTURBSEQUENCE

OPTIMAL SEQUENCE

TOTALDURATION

DISTRIBUTION

Total Project Build Duration Distribution

Model Validation Case Study

Egmond ann Zee Offshore Wind Farm

Egmond ann Zee Offshore Wind Farm

- Modelled Construction Operations:

• Monopile & TP Installation - Svanen (36 Units)

• Turbine Erection – A2SEA ‘Sea Energy’ (36 Units)

• Export Cable Installation (3 Units)

• Inter-Array Cable Installation (33 Units)

• Turbine Commissioning

• Wind Farm Reliability Testing

Validation Case Study

Egmond ann Zee Case Study

Stage 1 Results

- Monopile Foundation Installation Duration Distributions (Single Unit per Trip)

Duration [hrs] (March)

Duration [hrs] (June)

Duration [hrs] (September)

Duration [hrs] (January)

Iter

atio

ns

0

200

400

600

800

1000

50 100 150 200 250 300 350 400 450 500 550

0

200

400

600

800

1000

50 100 150 200 250 300 350 400 450 500 550

0

200

400

600

800

1000

50 100 150 200 250 300 350 400 450 500 550

0

200

400

600

800

1000

50 100 150 200 250 300 350 400 450 500 550

0

100

200

300

400

500

600

700

80 130 180 230 280 330 380 430 480

0

100

200

300

400

500

600

700

80 130 180 230 280 330 380 430 480

0

100

200

300

400

500

600

700

80 130 180 230 280 330 380 430 480

0

100

200

300

400

500

600

700

80 130 180 230 280 330 380 430 480


Stage 1 Results

- Turbine Erection Duration Distributions (2 Turbine Units per Trip)

Duration [hrs] (March)

Duration [hrs] (June)

Duration [hrs] (September)

Duration [hrs] (December)

Iter

atio

ns

Egmond ann Zee Case StudyStage 2 Egmond ann Zee project definition

- Segregated into 10 construction zones

- Single contractor per zone at any one time

- Construction sequence:

1. Foundation Installation

2. Sub-Sea Cable Installation

3. Cable Terminations

4. Wind Turbine Erection

5. Cable Testing

6. Wind Turbine Testing

7. Wind Turbine Commissioning


Stage 2 Results

- Monopile & Transition Piece Installation

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 50 100 150 200 250 300 350 400 450 500

Operation Duration (Days)

Itera

tions

O2C Predicted P(50) Project Build Duration

Egmond ann Zee Total Project Duration

O2C Predicted P(90) Project Build Duration4 Days

P(50) P(90)


Stage 2 Results

- Wind Turbine Erection

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 50 100 150 200 250 300 350 400 450 500


Itera

tions




P(50) P(90)


Stage 2 Results

- Wind Turbine Erection (without logistic downtime)

0

500

1000

1500

2000

2500

3000

3500

4000

0 50 100 150 200 250 300 350 400 450 500


Itera

tions



O2C Predicted P(90) Project Build Duration1 Day

P(50) P(90)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 50 100 150 200 250 300 350 400 450 500

Project Duration (Days)

Itera

tions


Stage 2 Results

- Total Project Build Duration




P(50) P(90)

Egmond ann Zee Case StudyConclusions

- Good level of agreement (weather downtime modelling)

- Modelling of project zones results in artificial delay (Egmond)

- Modelling as an EPC contract would result in a better agreement

- Complete project build duration within model’s P(50) to P(90) limits

SummaryThe value of O2C Modelling

- Allows resourcing sensitivity studies

- Allows cost benefit analysis

- Allows developer to assess & reduce contract interface risks

- Importantly allows for a novel visualisation of the project build

Thank You for Your AttentionNick Baldock - Garrad Hassan

Main Stand Hall 2. No. 2260

Contact details:

[email protected] Bristol (UK)

[email protected] Bristol (UK)

[email protected] Paris (France)

References:

Offshore Wind Farm Egmond ann Zee General Report,

Documents

Nick Baldock Garrad Hassan and Partners Ltd