The rapid development of wind farms across the world has led to questions regarding their potential impacts on the environment. Wind farms extract energy from the wind to produce electricity. This extraction of energy may have the potential to impact the local weather and climate. Furthermore, the impact of wind farms on the atmosphere can in turn feed back onto the operation of wind farms, affecting the efficiency of power production, as has been observed in large wind farms. This work explores the interaction between large wind farms and the atmosphere, through developing a new computer model to represent the influence of wind farms on the atmosphere.
Simulations of a large wind farm covering 10x10 km, similar in scale to the current largest offshore wind farms, show impacts on wind speed and turbulence, in both onshore and offshore cases. An impact is seen not only on the local wind, but also at distances of tens of kilometres downwind, at night, in the onshore case. There are major differences between daytime and night-time in the strength and structure of the wind farm wake. These differences in the wake in turn affect the power output of downwind wind turbines.
The enhanced turbulence within the wind farm causes a very small change in temperature. The near-surface temperature change is found to be smaller than in previous climate model studies, with a maximum increase of 0.5 at night. Little temperature change is seen during the day. Downwind, the temperature change is negligible. Current approaches for representing wind farms in climate models are found to be inappropriate and generally exaggerate the wind farm impacts seen. More sophisticated models such as the one developed in this work should be used instead.
Her thesis will soon be available to NORCOWE partners on Projectplace.