Thermal power generation faces risks from rising water temperatures and scarcity, worsened by decarbonization efforts that prioritize the retirement of lower-risk units. To reconcile energy security and climate goals, policymakers should factor hydroclimatic risks into power plant retirement and energy transition planning.

Recommendations for policy

Integrate hydroclimatic risks into decommissioning and retirement plans to avoid retaining high-risk yet large-capacity thermal units and ensure a safer, more resilient energy transition.

Prioritize regional hydroclimatic risk evaluations when developing decommissioning strategies to balance thermal power reliability with environmental sustainability effectively.

Develop and implement policies that simultaneously advance climate mitigation and adaptation in the energy sector, enhancing power system resilience.

Expand policy frameworks to address not only water scarcity but also emerging thermal constraints, such as rising water temperatures, by incorporating adaptive management strategies in energy and water sectors.

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BASED ON: S. Li et al. Nature Sustainability https://doi.org/10.1038/s41893-025-01692-9 (2025).

The policy problem

Thermal power, which relies heavily on cooling water, will remain essential for providing baseload and flexible generation during decarbonization. However, rising water temperatures and increasing water scarcity are undermining plant performance and threatening energy security, especially under stringent environmental flow and thermal discharge regulations. Current decommissioning strategies for thermal power plants rarely account for such hydroclimatic risks, leading to the unintended retention of certain large-capacity yet high-risk units that may underperform in future climate conditions.

The findings

We find that large thermal units, as a group, face greater hydroclimatic risks than smaller ones — both historically and under future climate change (Fig. 1a). Despite this higher group-level risk, larger units are typically prioritized for retention owing to environmental and economic considerations. This misalignment leads to disproportionate performance degradation (Fig. 1b), jeopardizing energy security across fuel types and climate scenarios. Incorporating an 80% hydroclimatic risk constraint into retirement strategies boosts system resilience by 26–37 percentage points but may result in retaining slightly older, higher-emitting units (Fig. 1c). Region-specific thresholds can help to balance energy security with environmental protection, but loosening environmental flow and thermal discharge regulations to offset risk would undermine aquatic ecosystems and integrated water management goals.

Fig. 1: Hydroclimatic risks and strategic decommissioning pathways.

a, Historical UCRs for global thermal units. b, UCRs for units prioritized for retention and retirement under the age-to-capacity ratio (ATC)-based strategy. c, Comparisons for units under ATC-based and UCR-based strategies. Figure adapted from Li, S. et al. Nat. Sustain. https://doi.org/10.1038/s41893-025-01692-9 (2025), Springer Nature Limited. The basemap is sourced from Natural Earth (https://www.naturalearthdata.com).

The study

We developed a global, unit-level assessment framework that links detailed thermal power unit characteristics (for example, fuel type, nameplate capacity and cooling water demand) with grid-level hydroclimatic data (for example, water temperature and discharge) to evaluate dynamically evolving hydroclimatic risks for each unit. We defined usable capacity ratio (UCR), the share of nameplate capacity operable under hydroclimatic constraints, as an indicator of risk arising from rising water temperatures and declining water availability under three climate scenarios: low (SSP126), medium (SSP370) and high (SSP585) warming, where lower UCR values denote higher risks. Using this framework, we separately assessed the hydroclimatic risks of thermal units prioritized for retirement versus retention, highlighting their implications for energy security.

Further reading

van Vliet, M. T. H. et al. Power-generation system vulnerability and adaptation to changes in climate and water resources. Nat. Clim. Change 6, 375–380 (2016). This article examines the vulnerability of global thermoelectric power generation to climate-driven water stress.

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (grants 42361144876, 42471021 and 42277482 to Y.Q.). S.L. acknowledges support from Peking University-BHP Carbon and Climate Wei-Ming PhD Scholars Program (WM202413). J.L. acknowledges support from the 111 Project (grant no. D25014), the National Foreign Experts Program (Category S) (grant no. S20240116), the Henan Province Foreign Scientist Studio for Synergistic Management of Water, Food, Energy, and Carbon (grant no. GZS2024013) and research projects (254000510004).

Author information

Authors and Affiliations

Key Laboratory of Water and Sediment Science, Ministry of Education, Peking University, Beijing, China

Shiyu Li & Yue Qin 1.

State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Peking University, Beijing, China

Shiyu Li, Qingsong Jiang, Yong Liu & Yue Qin 1.

College of Environmental Sciences and Engineering, Peking University, Beijing, China

Shiyu Li, Qingsong Jiang, Yong Liu & Yue Qin 1.

Institute of Carbon Neutrality, Peking University, Beijing, China

Shiyu Li, Yong Liu & Yue Qin 1.

Yellow River Research Institute, North China University of Water Resources and Electric Power, Zhengzhou, China

Junguo Liu 1.

South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China

Gang Yan 1.

Key Laboratory of Environmental Pollution and Greenhouse Gases Co-control, Ministry of Ecology and Environment, Chinese Academy of Environmental Planning, Beijing, China

Gang Yan & Yixuan Zheng 1.

Department of Earth System Science, Stanford Doerr School of Sustainability, Stanford University, Stanford, CA, USA

Steven J. Davis 1.

Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA, USA

Amir AghaKouchak 1.

Department of Earth System Science, University of California, Irvine, Irvine, CA, USA

Amir AghaKouchak 1.

United Nations University, Institute for Water, Environment & Health (UNU-INWEH), Richmond Hill, Ontario, Canada

Amir AghaKouchak 1.

School of Earth and Space Sciences, Peking University, Beijing, China

Xin Liu 1.

Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, China

Chaopeng Hong 1.

Southwest United Graduate School, Yunnan, China

Yong Liu

Authors

1. Shiyu Li
2. Junguo Liu
3. Gang Yan
4. Steven J. Davis
5. Amir AghaKouchak
6. Xin Liu
7. Chaopeng Hong
8. Yixuan Zheng
9. Qingsong Jiang
10. Yong Liu
11. Yue Qin

Corresponding authors

Correspondence to Gang Yan, Yong Liu or Yue Qin.

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Competing interests

The authors declare no competing interests.

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Cite this article

Li, S., Liu, J., Yan, G. et al. Balancing thermal power decarbonization and energy security under hydroclimatic risks. Nat Sustain (2025). https://doi.org/10.1038/s41893-025-01711-9

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Published: 09 December 2025

Version of record: 09 December 2025

DOI: https://doi.org/10.1038/s41893-025-01711-9