Cost of energy optimisation of offshore wind turbine pmg drive trains based on uncertainty

  • Kerri Hart

Student thesis: Doctoral Thesis


Offshore wind is a constantly evolving industry as the demand for clean renewable sources of energy continues to grow globally. The cost of energy (COE) is measure of the cost per unit of energy supplied by a provider over the lifetime of a project. Methods in which to reduce this cost are always a priority for parties involved in the design, installation and operation of a wind farm. This thesis explores the contribution of wind turbine drive train design and optimisation in the reduction of COE whilst providing a review of the most sensitive design parameters.Chapters 1 and 2 provide the background to the COE calculation for offshore wind turbines and introduces some of the key issues with current models and challenges for creating reliable designs. Chapter 3 outlines the COE model methodology and introduces base case results for 4 different drive trains with permanent magnet generators (three geared designs and one direct drive topology without a gearbox). Chapter 4 provides an optimisation process based on a genetic algorithm to allow the design to be improved whilst considering several constraints. Chapter 5 looks at the optimised designs under different price input conditions to assess the impact on the COE. Chapter 6 introduces the concepts of robust optimisation and optimisation under uncertainty to account for price variability associated with material used in the drive train.This thesis provides a novel approach to drive train optimisation whilst accounting for price uncertainty. The study highlights the key vulnerabilities for a design under material price fluctuations and presents design processes which include uncertainty and provide robust solutions for various drive train topologies.The effect of drive train design and optimisation suggests that direct drive topologies (that do not have a gearbox) can offer the lowest COE solutions. This is primarily due to the increase in reliability achieved by eradicating the failures associated with wind turbine gearboxes. This result supports current trends observed in large offshore wind turbines where many of the installed >6MW machines are direct drive permanent magnet generators. Additionally, a well-designed drive train has the potential to reduce the COE by up to 15% as discussed in this thesis.
Date of Award19 Sept 2019
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)
SupervisorAlasdair McDonald (Supervisor) & Olimpo Anaya-Lara (Supervisor)

Cite this