Global assessment of management strategies for clean water and energy provision under droughts, heatwaves, and compound events

Increases in the frequency and intensity of droughts, heatwaves, and their compound occurrence are placing growing pressure on both clean water provision and water-dependent energy systems, and their interactions worldwide. While many studies quantify the impact of climate extremes on clean water supply and energy systems, far less attention has been given to how countries are managing risks across these sectors.

This study provides a global assessment of management strategies for clean water and energy provision under droughts, heatwaves, and compound events, and assesses their implications for water–energy trade-offs. We especially focus on management strategies related to energy-intensive water supply options, including desalination, wastewater treatment, and inter-basin transfers, and water-intensive energy technologies such as hydropower and thermoelectric power.

We combined a structured literature review (focusing on the period 2000–2025) with an indicator-based global data analysis. Using semi-automated screening and manual review, we evaluate water–energy sector interactions and management strategies during droughts, heatwaves, and compound events. In addition, we complement this review with new national-scale indicators capturing water scarcity (water gap per capita), dependence on water-intensive electricity generation, thermoelectric cooling technologies, and reliance on energy-intensive water sources. This allows us to assess both “water-for-energy” and “energy-for-water” risks and to consistently compare reported strategies with underlying system vulnerabilities across countries globally.

The results show that energy-intensive water supply options such as desalination and wastewater treatment are widely promoted to reduce water scarcity, with growing emphasis in future adaptation pathways. However, even in several countries with large treatment capacity, these technologies address only a small share of total water gaps. On the energy side, adaptation strategies focus mainly on switches in cooling-system types, optimization in reservoir operation, and energy-mix diversification (e.g., shifting to technologies which do not require water such as wind and solar energy) to adapt to climate change and extremes (i.e., droughts, heatwaves).

Our study highlights several opportunities for more coherent clean water–energy management. In the water sector, treated wastewater can support energy provision by supplying cooling water for thermoelectric power plants and by enabling energy recovery through processes such as biogas or heat extraction. In the energy sector, locating water-intensive power generation in water-abundant regions for climate-smart energy planning in the future, and expanding water-independent renewable energy, emerge as key options to reduce pressure on scarce resources. The presented results provide a basis for future scenario design and modelling and offer a foundation for stakeholder engagement to assess joint clean water–energy transition pathways that align with regional socio-environmental conditions.