Open Access Publications

Permanent URI for this collection

Open access publications by faculty, staff, postdocs, and graduate students in the Center for Research in Wind.


Recent Submissions

Now showing 1 - 3 of 3
  • Item
    Comparison of individual versus ensemble wind farm parameterizations inclusive of sub-grid wakes for the WRF model
    (Wind Energy, 2022-06-02) Ma, Yulong; Archer, Cristina; Vasel-Be-Hagh, Ahmad
    Wind turbine wakes can be predicted somewhat accurately with mesoscale numerical models, such as the Weather Research and Forecast (WRF) model, via a wind farm parameterization (WFP) that treats the effects of the wakes, which are sub-grid features, on power production and the environment. A few WFPs have been proposed in the literature, but none has been able to properly account for the individual wakes within a grid cell or the effects of overlapping wakes from multiple turbines. A solution to these two issues is a WFP that includes both a wake model, which is a simplified analytical model of the wind speed (or wind power) deficit caused by a wake, and a wake superposition model, which accounts for overlapping wakes. Several such WFPs are developed here for the WRF model—based on the Jensen, the Geometric, and the Gaussian wake models coupled with two wake superposition methods (based on a squared deficit and a squared velocity superposition)—and tested individually, as well as combined together in an ensemble (EWFP), at two modern offshore wind farms. Most WFPs perform satisfactorily alone, but the EWFP generally outperforms them at both farms. The issue of resolved versus sub-grid wakes is explored for single- and multi-cell cases and for directions of alignment and non-alignment between the wind direction and the turbine columns. Although different combinations of wake loss and wake superposition models might be preferred at other wind farms, the general findings and detailed performance statistics given here might provide useful guidance in their selection. Abbreviations: EWFP - ensemble wind farm parameterization GM - geometric model WFP - wind farm parameterization WRF - Weather Research and Forecast model XA - Xie and Archer (2015)
  • Item
    Surface impacts of large offshore wind farms
    (Environmental Research Letters, 2022-05-25) Golbazi, Maryam; Archer, Cristina L.; Alessandrini, Stefano
    Future offshore wind farms around the world will be built with wind turbines of size and capacity never seen before (with diameter and hub height exceeding 150 and 100 m, respectively, and rated power exceeding 10 MW). Their potential impacts at the surface have not yet been studied. Here we conduct high-resolution numerical simulations using a mesoscale model with a wind farm parameterization and compare scenarios with and without offshore wind farms equipped with these 'extreme-scale' wind turbines. Wind speed, turbulence, friction velocity, and sensible heat fluxes are slightly reduced at the surface, like with conventional wind turbines. But, while the warming found below the rotor in stable atmospheric conditions extends to the surface with conventional wind turbines, with extreme-scale ones it does not reach the surface, where instead minimal cooling is found. Overall, the surface meteorological impacts of large offshore wind farms equipped with extreme-scale turbines are statistically significant but negligible in magnitude.
  • Item
    Marshaling ports required to meet US policy targets for offshore wind power
    (Energy Policy, 2022-02-16) Parkison, Sara B.; Kempton, Willett
    We analyze infrastructure needed for offshore wind power targets set by U.S. state and federal policies—specifically, manufacturing, vessels, and offshore wind ports. By examining cost-competitive turbine and project sizes and infrastructure challenges, we identify marshaling ports as a key bottleneck. Through elicitation of requirements from supply chain, port, and vessel experts, we identify the necessary attributes for marshaling ports and calculate the area needed to meet policy targets. US marshaling ports are currently insufficient to meet either state or federal power targets. We calculate state commitments from state contracts and policies: in sum, 40 GW by 2040. Federal targets from the Biden Administration are 30 GW by 2030 and 110 GW by 2050. Either target yields more demand for marshaling area than is currently available or planned. The shortage of marshaling area supply has incorrectly been attributed to lack of suitable U.S. locations. Instead, we attribute it to developers having built ports to support early, smaller projects, and having located them to incentivize state power contracts rather than developing ports for long-term, large-scale, and economically-efficient use. Additional land suitable for marshaling ports exists, but it requires commitment from port authorities and port investors to develop it for this purpose.
Copyright: Please look at individual material in order to see what the copyright and licensing terms are. Some material may be available for reuse under a Creative Commons license; other material may be the copyright of the individual author(s) or the publisher of the journal. Copyright lines may not be present in Accepted Manuscript versions so please refer to individual journal policies and/or look up the journal policies in Sherpa Romeo.