The water-energy nexus: why managing water stress is the key to the future of energy

Many countries face tighter competition for water across agriculture, cities and industry, alongside more frequent droughts and hotter summers. Simultaneously, electricity demand is also rising, in part due to higher cooling needs during heat events.

With those trends in mind, the power sector is both vulnerable to water stress and, depending on technology choices, can also intensify it. Navigating this balance becomes a reliability and investment issue, which can change over the lifetime of power assets as water conditions evolve. When river flows drop or intake water temperatures rise, thermal plants can face operational limits just when electricity demand peaks during heatwaves. Such fluctuations can shape permitting decisions, influence how system operators run the grid, and raise due diligence requirements for projects in stressed basins.

Power-generation technologies have sharply different water profiles. Choices about the generation mix and where infrastructure is built shape how exposed a country becomes to water-related issues that can limit operations, slow approvals, and worsen climate-driven water stress.

The relationship between water and electricity is especially visible in plant cooling. That is why it is important to distinguish between water withdrawal (the total volume taken from a source) and water consumption (the share not returned, often through evaporation) when comparing different power generation technologies.

The infographic below shows that wind and solar PV have low life-cycle water consumption, while steam-cycle options are more water-intensive, depending on cooling design.

Wind and solar PV require very little water for operation and have minimal life-cycle water use relative to water-cooled thermal generation. Scaling renewables can:

Not all low-carbon options are low-water, however. Thermo-electric technologies, including concentrated solar power (CSP) and geothermal, can require substantial water, depending on cooling design.

In practice, the largest water-risk and potential water-savings measures sit in four areas:

Where system conditions allow, prioritizing solar PV and wind reduces the need to run water-intensive thermal units during heat and drought stress. The benefit increases when renewables are paired with measures that allow higher utilization and secure integration.

Cooling system choices drive water withdrawals and consumption in thermal power generation. For any thermal capacity that remains necessary to meet peak demand and keep the grid stable, planners can reduce water risk by setting expectations on cooling performance.

India provides a clear illustration of how renewables and cooling policy interact to reduce water risk in the power sector (see infographic below). An IRENA and World Resources Institute analysis assesses how renewables and shifts in cooling technologies could change freshwater use in the country’s power generation by 2030. An ambitious shift to renewables and improved cooling could reduce water withdrawal intensity by up to 84% by 2030 and water consumption intensity by 25% relative to 2014. The policy message is simple: Scale low-water renewables and tighten cooling measures for the remaining thermal fleet.

Location determines competition with other users and exposure to climate variability. Screening projects against basin-level water stress and discharge constraints helps avoid stranded operational capability and conflict with other water priorities.

China’s experience shows why water stress, siting and cooling choices can become system-level planning constraints. An IRENA and China Water Risk assessment examines how alternative 2030 power-sector pathways affect water use and emissions intensity in the country. An estimated 45% of its power generation facilities rely on freshwater and are located in areas of high water stress (excluding hydropower). Higher renewables deployment and improved plant cooling could reduce water withdrawal intensity by 42%, water consumption intensity by 30%, and emissions intensity by 37% relative to 2013 (see infographic below). In water-stressed basins, generation planning and permitting should treat water availability and cooling as up-front constraints.

Water stress is seasonal and local. It is increasingly shaped by climate variability. Planning approaches should explicitly test the system against water-constrained operating conditions in the same way they would plan for fuel and network risks. A key test is whether planning frameworks can anticipate new water-sensitive electricity demands:

Power-sector choices can either reduce water stress or lock it in for decades. A renewables-based transition is not only a decarbonization pathway, but also a pragmatic risk-management approach for operating reliably in hotter and more water-constrained conditions. The main policy message is that water-smart electricity is achievable, but only if water considerations are embedded early in power-system planning, technology selection and investment rules.

The Global Future Council on Energy Nexus shares ideas and examples through its Energy Nexus Insights series, comprising blogs, articles and infographics; guides for public- and private-sector decision-makers; and sector analyses.