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Offshore CREYAP Part 1

38 teams have taken part in the first offshore Comparative Resource and Energy Yield Assessment Procedure (CREYAP) exercise

The conference session on Thursday 21 November 2013 entitled “Offshore Energy Yield Assessments: Challenges and Lessons Learned” will include the presentation and discussion of the results of the first offshore Comparative Resource and Energy Yield Assessment Procedure (CREYAP).

Between August and September 2013 wind data and information on turbine layout were provided to organisations for them to assess the expected energy yield for this wind farm. The submissions received from 38 organisations are now being analysed. This will allow the areas of largest discrepancy between methodologies to be highlighted and lead to valuable discussion regarding the challenges for accurate offshore yield assessments. Many thanks to all those who have submitted results, including the following organisations:

  • 3E, Belgium
  • AWS Truepower, USA
  • Barlovento Recursos Naturales, Spain
  • CENER, Spain
  • CIRCE – Research Center for Energy Resources and Consumption, Spain
  • DONG Energy Wind Power, Denmark
  • DTU Wind, Denmark
  • EMD International, Denmark
  • Enerpark Inżynieria Wiatrowa, Poland
  • EREDA SLU, Spain
  • Etha Ab, Finland
  • Fraunhofer IWES, Germany
  • Fujian Hydro Power, China
  • Gamesa Corporación Tecnológica, Spain
  • GL Garrad Hassan, UK
  • Grupo COBRA (EYRA), Spain
  • Ingham Consult ApS, Denmark
  • Lahmeyer International GmbH, Germany
  • Mott MacDonald, UK
  • Mytrah Energy (India) Ltd, India
  • Natural Power, UK
  • Prevailing Ltd, UK
  • REpower Systems, Germany
  • RES Group, UK
  • RSE S.p.A., Italy
  • Statoil, Norway
  • The Wind Consultancy Service, UK
  • Tractebel Engineering, Belgium
  • Vattenfall, UK
  • Wind Energy Corporation, Japan
  • Wind Prospect Group Limited, UK
  • WIND-consult GmbH, Germany
  • WindGuard, Germany
  • WindSim AS, Norway
  • Winwind Ltd, Finland
  • YCON BVBA, Belgium

This exercise builds on the two highly-successful CREYAP exercises for onshore wind that have been conducted to date:

Offshore CREYAP Part 1 exercise description

Offshore_CREYAP_Pt1_mapThe exercise is based on the under-construction Gwynt y Mor offshore wind farm, which will consist of 160 Siemens 3.6MW turbines. Using wind data provided, the 30+ organisations that have participated have derived the net energy yield for Gwynt Y Mor, accounting for wind speed variation across the site and wake effects.

Since the exact power and thrust curve for the turbines will not be known, this exercise will not be an accurate prediction of the actual Gwynt y Mor energy yield. It is intended purely as a comparative exercise using publically-available information about the wind farm.

A secondary exercise is also proposed, in which participants will derive the predicted wake impact of Gwynt Y Mor upon the operational North Hoyle offshore wind farm. This will facilitate a comparison of inter-farm wake models.

The deadline for submitting results has now passed but you may still access the data pack for reference by filling in the form below.

Download the Offshore CREYAP Part 1: Scope of Work, Inputs and Deliverables (PDF): this document outlines the scope of work for the Offshore CREYAP Part 1 energy yield comparison exercise and describes the inputs that are provided in the data pack and the results that participants were askeded to produce.

Note to all organisations that have submitted results: Tim Robinson, EWEA, will email your submission code within two days of receipt of your results spreadhseet. If you have not received your code please email : [email protected]. The submission code that will be used to refer to your submission in case of queries and in the presentation of the results of the comparison exercise at EWEA OFFSHORE 2013, Frankfurt, on 21 November 2013. In this way EWEA will keep the identity of each participant anonymous.

Complete the form to access the data pack webpage


EWEA wishes to thank the parties that have made this comparison exercises possible:

  • Renewable Energy Systems Ltd, The Crown Estate and The Carbon Trust for providing the data and preparing the data pack;
  • DTU Wind Energy for the analysis and presentation of the results at EWEA OFFSHORE 2013.


If you have any questions regarding the exercise or your submission please contact:
Tim Robinson, EWEA
Tel: +32 2 213 18 44
Email: [email protected]