Integrated pathways for sustainable energy-water nexus management in resource-dependent cities: A scenario-based assessment of Tangshan, China

Sustainable management of the energy-water nexus is critical for resource-dependent cities facing intensifying trade-offs between energy transitions and water security. However, a quantitative assessment of dynamic feedback between energy transition and water resource demands under alternative policies remains unclear. To address this challenge, this study integrates the Long-range Energy Alternatives Planning model with bottom-up water accounting to quantify energy-water interdependencies in Tangshan, China. Four policy-driven scenarios are simulated from 2023 to 2050, including reference, industrial structure optimization, energy structure optimization, and low-carbon development. Results reveal temporal trade-offs and structural shifts within the energy-water nexus under each pathway. Under the reference scenario, both energy production and water demand exhibit significant growth throughout the period. Water withdrawal and consumption increase to 12.09 × 108 m3 and 2.5 × 108 m3 by 2050, respectively. Industrial structure optimization reduces short-term withdrawal by 28.35 % and consumption by 29.4 % by 2030, while long-term water demand remains at a high level due to overreliance on coal-fired power. Energy structure optimization scenario supplies a share of clean energy in total electricity generation exceeding 95 %, mitigating energy transition risks in the mid-term through renewable energy deployment. It stabilizes water-consumption efficiency at 27.07 % while minimizing water withdrawal, peaking earlier at 7.02 × 108 m3 in 2035. Low-carbon development demonstrates significant advantages in controlling total energy production and water withdrawal through technological innovation and improved energy efficiency in the long term. Water withdrawal has decreased by 61.21 % by 2050 compared to the baseline scenario, while emerging technologies of carbon-capture-storage and waste-to-energy introduce new high-intensity water consumption sectors, increasing water consumption efficiency by 63.73 %. Sectoral analysis identifies the shift of water-intensive sectors from thermal power cooling toward carbon-capture-storage and waste-to-energy across scenarios. These findings suggest that single-dimensional strategies may not be sufficient in addressing the structural conflicts of the energy-water nexus. Building on these insights, a phased governance strategy of industrial structure optimization by 2030, renewable energy substitution by 2040, and integrating technological innovation in low-carbon and water-saving by 2050 is proposed to balance energy transition with hydrological resilience over time. The methodological approach and policy recommendations offer an adaptable implementation framework for other resource-dependent cities worldwide striving to resolve the complexities of energy-water nexus governance.