Techreport,
Modelling wind energy generation potential on seasonal timescales with impact surfaces
3. Seasonal-to-decadal climate Prediction for the improvement of European Climate Services (SPECS), (August 2014)
Abstract
Significant wind energy generation potential exists in regions where the mean wind speed is large. Of
these regions forecasts are only useful where there is significant inter-annual variability in wind speed.
However useful seasonal forecasts of wind generation potential can only be made where there is both
large mean and variability, and skill in wind prediction.
Seasonal climate models provide wind forecasts in the form of seasonal averages of 10m winds. To
naively use this average value to directly calculate the potential wind energy is flawed, due to several
reasons:
- A seasonal average masks subseasonal variability. Due to the nonlinear relationship between
wind power and wind speed, this cannot be ignored.
- Daily wind speed masks diurnal variability. Furthermore a turbine cannot operate constantly;
below a threshold wind it will not turn, and above a higher threshold it powers down to prevent
mechanical damage.
- Turbines are generally higher than 10m, due to the increase in wind speed with height 10m
winds must be scaled up.
- Wind power is related to air density, which is in turn related to temperature. Diurnal and
subseasonal variations in temperature affect the calculation of wind power. Seasonal forecasts
of temperature also have the potential to provide extra predictability for wind energy.
These factors are explored here, and a consideration of these factors has led to the creation of impact
surfaces: a tool to visualize the wind energy generation potential in 'climate space'.
