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Schlagwörter:
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Zusammenfassung:
Wind turbines remove kinetic energy from the atmospheric flow,
which reduces wind speeds and limits generation rates of large
wind farms. These interactions can be approximated using a
vertical kinetic energy (VKE) flux method, which predicts that
the maximum power generation potential is 26% of the instantaneous
downward transport of kinetic energy using the preturbine
climatology. We compare the energy flux method to the Weather
Research and Forecasting (WRF) regional atmospheric model equipped
with a wind turbine parameterization over a 105 km2 region in the
central United States. The WRF simulations yield a maximum generation
of 1.1 We·m−2, whereas the VKE method predicts the time
series while underestimating the maximum generation rate by about
50%. Because VKE derives the generation limit from the preturbine
climatology, potential changes in the vertical kinetic energy flux from
the free atmosphere are not considered. Such changes are important
at night when WRF estimates are about twice the VKE value because
wind turbines interact with the decoupled nocturnal low-level jet in
this region. Daytime estimates agree better to 20% because the wind
turbines induce comparatively small changes to the downward kinetic
energy flux. This combination of downward transport limits and wind
speed reductions explains why large-scale wind power generation in
windy regions is limited to about 1 We·m−2, with VKE capturing this
combination in a comparatively simple way.
