Energetica India Magazine - September 2022

tion from in-depth additional research”, commented Greg Poulos, CEO of ArcVe- ra Renewables. Considering the large magnitude and length of wakes predicted by WRF- WFP in the New York Bight lease ar- eas, and lack of validating data for the large hypothetical wind turbines used in the simulations, ArcVera consulted with Professor Julie Lundquist’s research group at the University of Colorado to consider the uncertainty in these model predictions of large, long-range wakes. Several tests of sensitivity to model con- figuration parameters were run by Arc- Vera, and the results of these tests show that the original configuration actually produced the weakest wakes of all the configurations tested. Further research is needed Engineering models commonly used to estimate wakes have been validated for internal wakes and nearby external wakes but have not been validated regu- larly at such long distances and have not been validated at all for large nameplate (> 12 MW) and rotor diameter (> 200 m) wind turbines. On the other hand, the WFP in WRF has been validated against SCADA re- corded production for an onshore case by ArcVera and it was accurate with re- spect to long-distance wakes within 10% at a 5-km range (distance between wind farms being studied). “In the onshore validation study that we conducted in Iowa, USA, wakes were found to travel over 40 km overland, in stable atmospheric conditions. Over the ocean, it is common for atmospheric sta- bility to be enhanced, especially when warm air flow passes over colder underly- ing water. We also surmise that the very large turbines used in the study produce unusually strong wakes that cannot easi- ly recover their lost momentum, especial- ly under enhanced atmospheric stability conditions.”, commented Mark Stoelin- ga, who leads Atmospheric Science Inno- vation at ArcVera. However, the WRF-WFP is a research tool that has been developed and validat- ed against significantly smaller and less energetic turbines than those to be used in the New York Bight (15 MW, 240-m rotor diameter), and there may be addi- tional adjustments to the WFP required considering the very large and distant external wakes it produced in these sim- ulations. Ultimately, the longer-term objective is to use operational wind speed measure- ments and production data of large, op- erational offshore wind plants near other large offshore wind plants. The prefer- ence would be to identify the effects of having the larger, +10 MWwind turbines would have on long-distance wakes. Arc- Vera welcomes the owners and operators of such large offshore wind facilities to collaborate with them to move the re- search forward and elevate the success of global offshore wind development. 42 energetica INDIA- September_2022 WIND ENERGY