Evaluating the impact of kinetic energy removal by wind turbines on the technical wind energy potential of the German Bight

Scenarios of energy transition in Germany project large wind capacity deployment in the German Bight by 2050. They use models that estimate technical potential or annual generation
by fixing energy loss from atmosphere - turbine interactions to 10% to manage computational
cost. This approach, which we call Fixed, underestimates losses as it discounts impacts of wind
resource depletion that manifest as reduced wind speeds and lowered turbine yields. We explore
the influence of kinetic energy (KE) removal by wind turbines and stability conditions on wind
resource depletion and turbine yield. Using wind speeds, turbine yields and capacity factor
estimates from three approaches that include the Fixed approach, a simplified representation
of atmospheric KE budgets and their depletion (KEBA), and mesoscale simulations from the
Weather Research and Forecasting (WRF) model with a wind farm parameterisation we investigate the predominant influence on the Bight’s potential that is relevant for energy scenarios.
WRF, the most physically comprehensive model among the three, reveals that reductions in
these estimates are highest during stable conditions. KEBA, which incorporates only KE removal effects, aligns closely with WRF. Under highly unstable conditions KEBA’s wind speed
and capacity factors estimates are within 10% and 20% of WRF ,respectively. Under stable
conditions they are within 20 and 45%. As unstable conditions dominate the German Bight,
KEBA estimates of technical potential are within 35% of WRF, suggesting that KE removal
primarily shapes depletion effects and technical potential. Disregarding it leads to an overestimation of almost 90%. Despite depletion effects, the Bight’s potential remains substantial,
generating about 200 - 250 TWh yr−1 or 3000 - 3400 full load hours yr−1 from a 72 GW
deployment. We conclude that using a simplified yet physical model of KE budgets provides
more representative technical potential estimates for energy scenarios compared to the fixed
approach.