Scaling effects of fixed-wing ground-generation airborne wind energy systems

• Published in: Wind Energy Science Vol. 7; no. 5; pp. 1847 - 1868
• Main Authors: Sommerfeld, Markus, Dörenkämper, Martin, De Schutter, Jochem, Curran, Crawford
• Format: Journal Article
• Language: English
• Published: Göttingen Copernicus GmbH 12.09.2022; Copernicus Publications
• Subjects: Aircraft; Alternative energy sources; Altitude; Clustering; Energy resources; Ground stations; Investigations; Offshore; Offshore operations; Optimization algorithms; Probability distribution; Velocity; Weather forecasting; Wind power; Wind speed; Germany
• ISSN: 2366-7443; 2366-7451
• DOI: 10.5194/wes-7-1847-2022

While some airborne wind energy system (AWES) companies aim at small, temporary or remote off-grid markets, others aim at utility-scale, multi-megawatt integration into the electricity grid. This study investigates the scaling effects of single-wing, ground-generation AWESs from small- to utility-scale systems, subject to realistic 10 min, onshore and offshore wind conditions derived from a numerical mesoscale Weather Research And Forecasting (WRF) model. To reduce computational cost, vertical wind velocity profiles are grouped into 10 clusters using k-means clustering. Three representative profiles from each cluster are implemented into a nonlinear AWES optimal control model to determine power-optimal trajectories. We compare the effects of three different aircraft masses and two sets of nonlinear aerodynamic coefficients for aircraft with wing areas ranging from 10 to 150 m2 on operating parameters and flight trajectories. We predict size- and mass-dependent AWES power curves, annual energy production (AEP) and capacity factors (cf) and compare them to a quasi-steady-state reference model. Instantaneous force, tether-reeling speed and power fluctuations as well as power losses associated with tether drag and system mass are quantified.