A critical evaluation of wind turbine technology, leading to the development of 20mw multi rotor systems

  • Michael John Branney

Student thesis: Doctoral Thesis


The development of the conventional wind turbine from conception to modern day has been based on evolutionary and incremental design changes. Current existing commercial horizontal axis machines have yet to breach the 6MW power rating without significant cost penalties. The reason for this is primarily due to the negative effects of the square cubed law which shows that any increase in turbine diameter will lead to a cubic increase in turbine mass for only a square increase in power output.;Unfortunately, this universal truth can only be delayed and not ignored by advances in wind energy systems and it is therefore probable that conventional machines are nearing their power rating limits.;This project is focused firstly on a concerted review and evaluation of the wind energy design space followed by a more detailed study of those systems which theoretically should scale well with size and which may allow the wind industry to move to individual ratings of 10MW and beyond. Multi rotor systems with ratings of 20MW and above have been identified as serious contenders when considering cost of energy - the reduction of which, is a primary objective of the wind industry.;Detailed cost analysis, conducted after extensive development of the multi rotor concept has found that multi rotors can provide cost of energy at around 85% of conventional 10MW single rotor machines and around 82% of a conventional 20MW machine in a far-offshore environment.;More specifically, this thesis details the development of the multi rotor system from initial concept, considering all the main engineering points and presenting them in a useful way to alleviate concerns and pioneer the way for future research into the concept.
Date of Award14 Sept 2017
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)
SupervisorBill Leithead (Supervisor) & Peter Jamieson (Supervisor)

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