Nesting Ecology of a Population of Gopherus agassizii at a Utility-Scale Wind Energy Facility in Southern California

Copeia ◽  
2012 ◽  
Vol 2012 (2) ◽  
pp. 222-228 ◽  
Author(s):  
Joshua R. Ennen ◽  
Jeffrey E. Lovich ◽  
Katherin P. Meyer ◽  
Curtis Bjurlin ◽  
Terence R. Arundel
2018 ◽  
Vol 99 (6) ◽  
pp. 1472-1477 ◽  
Author(s):  
Jesika P Reimer ◽  
Erin F Baerwald ◽  
Robert M R Barclay
Keyword(s):  

2021 ◽  
Author(s):  
Thomas Haas ◽  
Jochem De Schutter ◽  
Moritz Diehl ◽  
Johan Meyers

Abstract. The future utility-scale deployment of airborne wind energy technologies requires the development of large-scale multi-megawatt systems. This study aims at quantifying the interaction between the atmospheric boundary layer (ABL) and large-scale airborne wind energy systems operating in a farm. To that end, we present a virtual flight simulator combining large-eddy simulations to simulate turbulent flow conditions and optimal control techniques for flight-path generation and tracking. The two-way coupling between flow and system dynamics is achieved by implementing an actuator sector method that we pair to a model predictive controller. In this study, we consider ground-based power generation pumping-mode AWE systems (lift-mode AWES) and on-board power generation AWE systems (drag-mode AWES). For the lift-mode AWES, we additionally investigate different reel-out strategies to reduce the interaction between the tethered wing and its own wake. Further, we investigate AWE parks consisting of 25 systems organized in 5 rows of 5 systems. For both lift- and drag-mode archetypes, we consider a moderate park layout with a power density of 10 MW km−2 achieved at a rated wind speed of 12 m s−1. For the drag-mode AWES, an additional park with denser layout and power density of 28 MW km−2 is also considered. The model predictive controller achieves very satisfactory flight-path tracking despite the AWE systems operating in fully waked, turbulent flow conditions. Furthermore, we observe significant wake effects for the utility-scale AWE systems considered in the study. Wake-induced performance losses increase gradually through the downstream rows of systems and reach in the last row of the parks up to 17 % for the lift-mode AWE park and up to 25 % and 45 % for the moderate and dense drag-mode AWE parks, respectively. For an operation period of 60 minutes at a below-rated reference wind speed of 10 m s−1, the lift-mode AWE park generates about 84.4 MW of power, corresponding to 82.5 % of the power yield expected when AWE systems operate ideally and interaction with the ABL is negligible. For the drag-mode AWE parks, the moderate and dense layouts generate about 86.0 MW and 72.9 MW of power, respectively, corresponding to 89.2 % and 75.6 % of the ideal power yield.


2021 ◽  
Author(s):  
Shellie R. Puffer ◽  
Laura A. Tennant ◽  
Jeffrey E. Lovich ◽  
Mickey Agha ◽  
Amanda L. Smith ◽  
...  

2018 ◽  
Vol 27 (12) ◽  
pp. 851 ◽  
Author(s):  
Jeffrey E. Lovich ◽  
Mickey Agha ◽  
Joshua R. Ennen ◽  
Terence R. Arundel ◽  
Meaghan Austin

Wind turbine-induced fires at a wind energy facility in California, USA, provided an opportunity to study the before and after effects of fire on a population of protected Agassiz’s desert tortoises (Gopherus agassizii) in the Sonoran Desert, a species and ecosystem poorly adapted to fire. We compared annual activity areas (AAs) of tortoises in 2011 and 2013, before and after two 2012 fires, with those of tortoises in adjacent areas unaffected by the same fires. Tortoises in both AAs affected by fire or unaffected by fire occupied the same general AAs in 2013, after the fires, as they did in 2011, before the fires. Some tortoises had both their 2011 and 2013 AAs completely or almost completely within the areas burned by the 2012 fires, despite the proximity of unburned habitat. None of the tortoises with 2011 AAs subsequently unaffected by the 2012 fires shifted their AAs into burned habitat in 2013. For the fire-affected group of tortoises, the mean percentages of 2011 and 2013 AAs burned by the 2012 fires were not significantly different, showing fidelity to the burned areas. Tortoises in both groups generally occupied consistent AAs, even post fire, placing them at potential risk of exposure to unfavourable burned habitat.


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