Standards and Practices - Structural Integrity of Offshore Wind Turbines - page 46

The first DNV offshore wind guideline, Design of Offshore Wind Turbine
Structures (DNV-OS-J101), was issued in June 2004. The most recent
version was issued in October 2010 (DNV 2010a). It covers support
structures and foundations for offshore wind turbines and meteorolog-
ical towers; the foundations guideline draws heavily upon API-RP-2A.
DNV-OS-J101 covers some elements of floating offshore wind turbines.
Common requirements between oil and gas floating structures and wind
turbine floating structures are covered in other DNV standards. The next
guideline issued was DNV-DS-J102 (originally in 2006; the latest version
was issued in 2010), which covers blades (DNV 2010b). The DNV-OS-J201
guideline, issued in 2009, covers design and certification of the offshore
transformer station (electric service platform) (DNV 2009). Design and
certification requirements are combined in the DNV documents.
GERMANISCHER LLOYD
GL was an early leader in developing guidelines for wind turbine design.
Its success has grown out of the popularity of wind energy in Germany
and the country's requirement of German engineering approval. These
factors gave GL exclusive certification authority on all German installa-
tions, a monopoly that still exists. GL's Guideline for the Certification of
Offshore Wind Turbines, 2nd edition, 2005, also called the GL Bluebook,
is perhaps the first to be widely used (GL 2005). The GL Bluebook cov-
ers all structures, systems, and components for offshore wind turbines
and their support structures and foundations. However, it does not cover
offshore electric service platforms, nor does it specifically cover floating
support structures for offshore wind turbines. The GL Bluebook is highly
prescriptive, and as such it is viewed by some in the industry as inflexi-
ble and restrictive in its applications. As with the DNV guidelines, design
and certification requirements are combined.
GL has remained active in international standards development and
European wind energy research. A major contributor to the IEC standards,
GL continues to update its Bluebook to reflect the IEC standards while
retaining requirements needed to comply with Germany's regulations.
The Bluebook remains the most comprehensive guideline on land-based
and offshore wind turbine requirements.