From the Abstract:
This framework was used to design fixed-wing ground-generation (GG) AWE systems based on the objective of minimising the levelised cost of energy (LCoE).
From the Conclusions:
An MDAO framework was developed to understand the scaling behaviour of AWE systems using LCoE as the design objective to conduct a holistic system performance assessment. This was applied to the fixed-wing GG AWE concept. System design parameters such as the wing area, aspect ratio, maximum wing loading, maximum tether stress, and the power crest factor were chosen as independent variables to systematically explore the design space. These parameters were optimised for the system sizes of 100, 500, 1000, and 2000 kW.
The minimum LCoE was found for the 500 kW system, and the extractable power per unit wing area shows diminishing marginal gain with increasing wing area. This shows that there is no distinct benefit to upscaling the systems to multiple megawatts in terms of LCoE. This outcome is due to the penalising effect of the kite’s weight on energy production and costs. Increasing rated power demands a larger kite, and since the mass increases rapidly with size, this has a negative effect since part of the aerodynamic force is used to counter the gravitational force. As a result, there is an increase in the cut-in wind speed, followed by an increase in the rated wind speed. Therefore, we see a decrease in capacity factor with increasing rated power.
Here, rigid (fixed) kites in yo-yo mode are studied. My opinion: couldn’t we wait for the actual implementation of a 10 kW (for example to power a house) fixed kite AWES before extrapolating toward a 500 kW AWES? But maybe we’ll have to wait still a long time even for a 10 kW fixed kite AWES, otherwise pursue with yo-yo flexible kites (some tangible results), or explore other architectures, or move on…