Conference Publication Details
Mandatory Fields
Kevin Coffey, Eamon McKeogh, Alfredo Pena and Paul Leahy.
2nd International Conference on Energy & Meteorology
Is there a value in including atmospheric stability in wind resource assessments in the marine environment?
Optional Fields
offshore wind; vertical extrapolation; remote sensing; sea surface temperature; surface fluxes; North Sea; marine atmospheric boundary layer

Accurate wind resource assessments reduce uncertainty in wind farm energy yield projections. This is particularly important offshore where development costs are high. The lack of hub height measurements of wind speed may require the extrapolation of observed wind speeds from lower measurement heights. The power law and logarithmic profile are the two most frequently used techniques. As these methods assume neutral stability, the application of an atmospheric stability correction term may lead to significant improvements in the predictions of the Vertical Wind Profile (VWP). The aim of this study is to find the most accurate method of modelling the VWP in the marine environment. Influences such as: (i) the required time resolution of data; (ii) temperature measurements; (iii) measurement heights; (iv) the parameterisation of sea surface roughness based on fetch type and (v) the necessary measurement parameters to model the VWP are investigated. Analysis of measurements from the Egmond aan Zee offshore wind farm and a site on the east coast of Norway are presented. Uncertainty remains over the most accurate method of calculating the Obukhov Length based on standard 10 minute time averaged measurements. Monin-Obukhov theory is valid in a limited range of conditions. To carry out a comprehensive wind resource assessment, the use of the entire dataset is desirable. Filtering the data to conform to M-O theory may lead to a large reduction in the time series of measurements used. Therefore, a trade-off must be made between temporal coverage of the measurements and strict compliance with M-O theory.

Higher Education Authority (GREP-Engineering)
Grant Details