Airborne wind energy resources: key advantages for the energy transition in Spain

In the way towards fully renewable power systems, the variability of conventional renewables represents a fundamental challenge. One of the options to tackle this issue is to exploit the complementarity between different renewable energy sources and technologies. Airborne wind energy (AWE) technology can tap the energy of winds at several hundred meters height, where winds are stronger and less variable than at the height of conventional wind turbines. The deployment of AWE systems is being hindered by their higher present costs, associated to their early development phase, but their large potential advantages point to future highly competitive costs if there are early adoption opportunities that accelerate the progress of this technology.

The aim of this study is to analyse the potential added value of AWE resources over Spain, in terms of temporal complementarity to mainstream renewables (onshore wind and photovoltaic energies) and adaptation to demand. Using data from a high resolution reanalysis (CERRA, Copernicus European Regional Reanalysis) and the AWERA tool [1] for analysing AWE resources, complementarity between AWE resources and conventional renewables is evaluated using actual PV and wind energy production data from the Spanish Transmission System Operator (Red Eléctrica Española), while demand data from the same source are used to explore adaptation to demand.

We focus on the summer season. This season is associated to distinct problems for a system based on conventional renewables, due to the strong seasonal decrease of conventional wind energy and the simultaneous increase in power demand for air cooling. Summer power demand may even exceed winter demand in the future, due to climate change. Despite its summer production peak, PV energy covers only part of the day. 

The high summer temperatures in Spain are associated with a particular seasonal low pressure system over the Iberian Peninsula, the Iberian thermal low [2]. The corresponding wind fields at heights of several hundred meters above the surface show a very interesting daily cycle over certain areas of Spain, with strong complementarity to PV generation, while the vertical wind variations reveal substantial advantages with respect to conventional wind energy. Consequently, AWE resources could make a significant contribution to the energy transition in Spain, filling some of the gaps of mainstream renewables.

References
[1] Thimm, L., Schelbergen, M., Bechtle, P., Schmehl, R.: The Airborne Wind Energy Resource Analysis Tool AWERA. 9th International Airborne Wind Energy Conference (AWEC 2021). Available at: http://resolver.tudelft.nl/uuid:ba0c7fb2-baff-4110-9a51-c27a8498663b

[2] Hoinka, K. P., Castro, M. D. (2003). The Iberian peninsula thermal low. Quarterly Journal of the Royal Meteorological Society, 129, 1491-1511.