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Conference programme 

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Poster session

Lead Session Chair:
Stephan Barth, Managing Director, ForWind - Center for Wind Energy Research, Germany
Philip Totaro Totaro & Asssociates, Germany
Philip Totaro (1) F P
(1) Totaro & Asssociates, Hamburg, Germany

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Presenter's biography

Biographies are supplied directly by presenters at OFFSHORE 2015 and are published here unedited

Philip Totaro is the Founder and CEO of Totaro & Associates, a market research and innovation strategy consultancy with offices in Hamburg, Germany and Houston, TX. Mr. Totaro is regarded worldwide as the foremost expert on wind industry technology and IPR matters. He has helped cultivate and disposition over 500 innovations, and his assessments have led to over 300 issued patents. His strategic market analysis has led to the funding justification of over $500M in R&D investment and the development of multi-million dollar product and service offerings. He has provided legal and technical due-diligence for over $1B in M&A.


Design of a 10MW Drivetrain Architecture


Drivetrain architecture still plays an important role in overall system reliability and energy efficiency. The known reliability issues with conventional gearboxes is leading to investigation and implementation of alternative configurations, such as two-stage gearboxes with a medium speed (100 - 400 rpm) generator, single stage gearboxes with a low speed (~90 rpm) generator, as well as direct drive.


Through a comprehensive evaluation of proposed technology architectures, a review of commercially available technical solutions, as well as feedback from turbine OEMs and drivetrain manufacturers, we will explore the optimal future concept which can deliver reliability, efficiency with an architecture which is optimized for O&M. We will benchmark performance and cost competitiveness of each type of drivetrain solution and show the cost and performance benefits of a turbine architecture which can exceed 10MW.

Main body of abstract

Improvements in three-stage gearboxes have resulted in improved reliability in the past 15 years. Nevertheless, despite improvements in failure rates and MTRS, conventional gearboxes still represent one of the components with the largest contribution to turbine down-time for both on and offshore. Improvements in bearing life, gear wear rates, as well as lubrication system effectiveness has had direct and quantifiable impact on gearbox life.

Two-stage gearboxes are now commercially available, but the recent introduction points to a lack of operational data to demonstrate long-term reliability. These designs offer advantages around part count while still maintaining generator efficiency in a compact size.

Single-stage gearboxes have gone through some conceptual design work, however, lack of commercial implementation of such designs indicates this will require more study and testing in the future before acceptance will occur. Numerous design concepts are being investigated and patented, and preliminary analysis suggests a 10% COE impact vs. three-stage due to a reduction in part count as well as a higher generator rpm with improved efficiency vs. low speed direct drive technology.
The push towards direct drive has resulted in several commercially available products comprising a low speed PMG or Wound Synchronous generator. While typically thought to be most useful for offshore, the viability of direct drive a lower power ratings for onshore applications has seen some success, albeit at a cost. Typically 20 - 30% higher BOM cost vs. conventional three-stage, the direct drive solutions still have a ways to go when it comes to COE parity.


Drivetrains are still a key component within the turbine for efficient energy transfer. Nowadays direct drive is no longer a novelty, it has become more mainstream with multiple manufacturers developing designs for both on and offshore. However, for future designs at 10MW and above, a single stage gearbox with a 90rpm generator appear to offer the best possible solution for performance and serviceability.

Learning objectives
1. What is the enabling technology behind a drivetrain for a 10MW plus turbine?
2. What future technology developments will prove efficient with optimize O&M cost?
3. How does the optimal architecture benchmark against conventional technology?