Continental and inter-continental complementarity of solar-wind and hydropower

Weather and climate fluctuations cause significant variations in renewable electricity production, necessitating substantial energy storage to address energy drought periods. To meet this need, renewable electricity systems rely on a relatively small share of hydropower storage to regulate climate-induced variability. Using daily hydroclimatic data and information about renewable power systems across Europe and Africa, we quantify the complementarity of solar, wind, and hydropower energy components within the continental climate systems.

Our findings reveal that existing hydropower reservoirs in Europe provide sufficient energy storage to overcome energy drought periods, but only under specific conditions: renewable electricity production must incorporate appropriate shares of wind and solar power, and the production-demand system must be managed at a continental scale. Spatiotemporal coordination of solar, wind, and hydropower can achieve a virtual energy storage gain (VESG) several times greater than the capacity of existing hydropower reservoirs. The most significant benefits from such management occur over distances of 1,200–3,000 km, underscoring the importance of continental- and intercontinental-scale planning for future renewable energy systems.

Since Africa’s current electricity generation is only one-fourth of Europe’s, we analyzed inter-hemispheric complementarity between the continents under various scenarios for hydropower, solar, and wind power development. The intercontinental complementarity offers the potential for even greater VESG and represents a critical factor for designing future renewable energy systems. Such designs must optimize between multiple considerations, including also the localization of power plants, transmission needs, and environmental constraints.