Offshore wind energy is rapidly growing, but what happens when more and more wind turbines deplete the regional wind energy resource?
Offshore wind energy is a key component in the energy transition in Germany, with the German Government aiming to expand installed capacity to 70 GW by 2050. But with more wind turbines installed within a region, the more they deplete the regional wind resource. This results in lower wind speeds, lower turbine efficiencies, yielding overall less electricity compared to the case in which this depletion effect is not considered. We evaluated this effect with colleagues from DTU Wind Energy and Agora Energiewende a few years ago. The outcome is that the depletion effects are significant and important, and, at the same time, offshore wind energy can nevertheless contribute substantially to German electricity needs. These outcomes are summarized in this Agora report and this blogpost.
In the new paper, these insights are summarized in a shorter and more accessible way. The energy transition is really important, yet also hotly debated, with a lot of misinformation circulating. For a more rational and informed discussion, it is critical to have solid and objective approaches available, approaches that are transparent and understandable, which the increasingly complex numerical weather simulation models are not. I hope to contribute to such a greater understanding with this paper. The paper describes our physics-based KEBA approach and how it is applied to evaluate the scenarios of offshore wind energy in the German Bight. The KEBA approach is physical yet simple – it simply budgets kinetic energy fluxes of the lower atmosphere of the region, the stuff that wind turbines need to generate electricity. KEBA works very well, able to reproduce the results of the much more complex numerical simulations with the WRF model. I find this scientifically quite satisfying, that one can get the relevant insights with just a little bit of essential physics.