DNV GL © 2013 SAFER, SMARTER, GREENER DNV GL © 2013

DGF/DONG Seminar – Geotechnical Engineering in Offshore Wind

1

- From a certification perspective

2014-04-01

Gentofte 2014-04-01

Liv Hamre

DNV GL © 2013

Offshore Wind - Combining DNV competences

2

Global leader in project

risk and certification of

offshore wind projects

25 years of hands-on

experience with wind

turbines

40+ years of offshore

oil & gas experience

DNV GL © 2013

2014-04-01

3

Founded 1864

Hovik, Norway

10,400 employees

Dedicated competences in:

Tankers

Offshore Classification

Power & Transmission

System certification

Merger of DNV & GL: Combining two major players

Founded 1867

Hamburg

6,700 employees

Dedicated competences in:

Container ships

Energy efficiency

Marine warranty

Renewables

DNV GL Group

Shared ambition for quality and

innovation

Head office in Hovik

16,000 employees

A leading company in:

Classification

Oil & Gas

Energy

Business Assurance

DNV GL © 2013

DNV GL Group - operating from Sept 12

DNV Foundation Mayfair

The world’s leading ship and offshore classification society and maritime advisory.

Hamburg, Germany

Appr. 6000 employees

A leading technical advisor to the global oil and gas industry

Høvik, Norway

Appr. 4500 employees

An energy powerhouse, supporting customers across the energy value chain Arnhem, Netherlands Appr. 3000 employees

One of the world’s leading certification bodies Milan, Italy Appr. 2000 employees

Maritime Oil & Gas Energy Business Assurance

Global Shared Services - Appr. 1500 employees

DNV GL Group Headquarter: Oslo, Norway

Group President & CEO: Henrik O. Madsen

63.5% 36.5%

Software

2014-04-01

4

DNV GL © 2013

World’s largest certification body for renewable energy

Services:

Component Certification

Type Certification

Project Certification

Training & Seminars

Standards & Guidelines

Clients:

Manufacturers

Project Developers

Owners / Operators

Investors

Government / NGOs

Industries:

Onshore Wind

Offshore Wind

Wave + Tidal

Solar

5

2014-04-01

DNV GL © 2013

Guidelines and accreditation strategy Harmonize 6 accreditations and 25 guidelines Focus on IEC interpretation

1. All guidelines remain valid

2. All guidelines will be continued

3. Harmonization of 25 guidelines by DNV GL

4. Harmonization of IEC interpretation

5. Equal services worldwide, regardless of location

6. Certificates will remain (subject to client demand)

6

2014-04-01

6

DNV GL © 2013

Wind farm certification

Pro

jec

t Ce

rtifica

te

Site Conditions

Assessement

Design Basis Evaluation

Integrated Load Analysis

Support Structure Design

Evaluation

Support Structure Manuf.

Surveillance

Commissioning

Surveillance

Transportation & Install.

Surveillance

Final Evaluation

Project Characteristics

Measurements

Project Certificate

Wind Turbine / RNA

Manuf. Surveillance

Wind Turbine / RNA

Design Evaluation

Other Installations Manuf.

Surveillance

Other Installations Design

Evaluation

Operations & Maintenance

Surveillance

Type Certificate

De

sig

n B

as

isD

es

ign

Ins

tal-

latio

n

Co

mm

is-

sio

nin

g

Ma

nu

fac-

turin

g

In-

se

rvic

e

7

DNV GL © 2013

Onshore Wind Farms

Covered by national standards

In European Countries, Eurocode is

governing

Eurocode 7 part 1 – Geotechnical Design

Eurocode 7 part 2 – Ground Investigation

and Laboratory Testing

– Gives requirements to amount of testing

and calculations for different design

categories

– According to the German regulations, a

WTG structure is geotechnical category 3

8

DNV GL © 2013

Offshore Wind Farms

2014-04-01

9

DNV-OS-J101 – Design of Offshore Wind Turbine Structures

DNV-OSS-901 – Project Certification of Offshore Wind Farms

DNV GL © 2013

Pre-certification work

In addition to the verification activities

necessary for project certification DNV may

evaluate or verify technical documentation

prepared prior to the project design and

implementation. Such verification activities

may include:

– Audit of geotechnical field operator and

geotechnical laboratory

– Soil investigation and laboratory test

program

– Concept / model evaluation

10

DNV GL © 2013

Geotechnical Site Investigations

The extent of soil investigations and the

choice of soil investigation methods shall

take into account the type, size and

importance of the wind turbine structure,

the complexity of soil and seabed

conditions and the actual type of soil

deposits.

The area to be covered by soil

investigations shall account for

positioning and installation tolerances.

For multiple foundations such as in a

wind farm, the soil stratigraphy and

range of soil strength properties shall be

assessed within each group of

foundations or per foundation location, as

relevant.

11

DNV GL © 2013

Design Basis

The geotechnical input to the design basis can consist of:

– Factual data

– field and laboratory test results

or

– Derived parameters

– design shear strength profiles and angles of internal friction

– design soil stiffness parameters

or

– Derived parameters and methodology

– design shear strength profiles and angles of internal friction

– design soil stiffness parameters

– skin friction and tip resistance profiles for axial pile design

– P-Y curves for lateral pile behaviour

In all cases, it is important that all principles are agreed upon before the detailed design of the wind turbine foundation starts

12

DNV GL © 2013

Geotechnical Design

Risk based verification

Guidelines in the standard – it is

allowed to carry out more detailed

analyses!

The verification may contain

independent calculations if

– The foundation type is novel

– The designer is unexperienced

– The soil data are limited or of poor

quality

– The documentation is of poor quality

2014-04-01

13

Incremental displacements – indicates failure mode

DNV GL © 2013

SAFER, SMARTER, GREENER

www.dnvgl.com

14

2014-04-01