全球智库信息集成服务系统

China’s power sector is its largest source of greenhouse gas emissions and also its biggest industrial water user. As a result, current and future decisions about electricity generation—and energy efficiency—will have profound impacts on both global climate and domestic water resources.

To offer suggestions on how to reduce the environmental impact of this growing industry, the World Resources Institute (WRI) evaluated the climate and water implications of over 20 combinations of power- generating technology and cooling-systems used or proposed in China and other countries. We developed the Water–Climate Impacts Bubble Chart to communicate potentially complex analytical results in a simple, visual manner to help decision-makers better understand the trade-offs between water use, climate impacts, and capital investment in the power sector. While this approach was developed with primarily Chinese data, other countries considering power generation technologies might also find it useful. Our research offers several key observations:

Employing energy-efficiency measures and technology is by far the most effective strategy for reducing both greenhouse gas emissions and water impacts. Rather than increasing plant generation capacity, energy efficiency measures leverage consumption efficiency to increase available electricity supply, showing a net positive impact on both greenhouse gas emissions and water use. Furthermore, this method is the most cost-effective approach among the options considered.

Of the renewable power generation technologies, run-of-river hydroelectric and wind power stand out as the alternatives with relatively low cost and low environmental impact. However, not all renewables have a positive impact on water. Concentrated solar power (CSP) plants, for example, while ideal for some of China’s sunniest and driest locations, require twice as much water as coal-fired plants equipped with the same closed-loop cooling system.

Carbon capture and storage (CCS) could cut the greenhouse gas emissions of pulverized-coal -fired power plants by 80 to 90 percent, but it would lead to a 90 percent increase in capital costs, a 15 to 30 percent decrease in power generation efficiency, and doubled water consumption. When retrofitting or designing new pulverized-coal plants with CCS, water availability should be carefully evaluated.

China’s national government has established strict water resource management requirements, setting mandatory limits on water withdrawal, efficiency, as well as water quality. These new limits have signaled China’s determination to improve the sustainability of water use. While there is no silver bullet to solve China’s water-climate conundrum, we offer several recommendations to help manage the water-energy trade-off in the Chinese power sector:

• China should devise policies to regulate water use in the power generation industry and establish sectoral water withdrawal quotas at the national, regional, and local levels.

• China should continue to promote end-use energy efficiency to reduce greenhouse gas emissions and conserve water.

• Wind and solar is the best option for China’s water-scarce areas, while run-of-river hydropower is most suitable for areas where water resources are available.

• Shifting to closed-loop or dry-cooling systems is recommended for China’s thermoelectric power plants.

• Policymakers should consider regional water distribution and avoid building low-carbon but water-intensive technologies (e.g. nuclear, CSP, and CCS) in water-stressed areas.