*4.2. BAU Water Consumption Scenario in 2020*

According to the "Power Development Strategic Research Report 2013" by CEC, the capacity of China's coal power plants in 2020 is expected to reach 1100 GW, and coal power bases will account for 55% of total newly-constructed plants. The BAU power demand and power planning is shown in Table 5.


**Table 5.** BAU (business-as-usual) power demand and power planning.

Assume constant water consumption rates, we can estimate the business-as-usual (BAU) scenario of water consumption by coal power plants in these coal power base provinces in 2020 (Table 6). According to the BAU scenario, it is estimated that water consumption for coal power generation will double during 2012–2020, provided that the comprehensive water consumption rates and the composition of cooling system are unchanged (Figure 5). It is worthwhile pointing out

that all these coal power bases are puzzled by water shortage, and a double growth in water demand will certainly break the balance of water ecology system in these regions.


**Table 6.** BAU Water consumption by thermal power plants in coal power base provinces, 2020.

**Figure 5.** 2020 BAU *vs.* 2012 water consumption by coal power in coal power base provinces.

Furthermore, current water consumption by the power generation is substantial in volume and critical to its operation, but pressures of population growth, hydrological variability and climate change will complicate the issue. Water consumption in these provinces is always constrained by available supply and consumption in other industries is relative stable in the past. Hence, we hypothesize that water consumption in other industrial sectors will hold constant during 2012–2020, and then we can update the percentage of coal power/industrial water use for these provinces in 2020 (Figure 6). According to the estimate, with the exception of Gansu province, in the other five provinces, the percentages of coal power/industrial water use will be largely enlarged. In Shanxi and Ningxia provinces, coal power is expected to consume 30% of industrial water use in the BAU scenario; while in Xinjiang, Inner Mongolia and Shaanxi, coal power is expected to consume around 20% of industrial water use. In other words, the BAU scenario envisions higher possibility of water resource conflicts in these provinces.

#### **5. Water Conservation Measures and Alternative Scenario**

Our projected result in these provinces has clearly indicated that serious water crisis will be likely to erupt in the BAU scenario. A strong implication is that the Chinese Government must take water resource constraint into consideration as a critical point in its overall sustainable development plan, in addition to energy supply and environment protection. The point is that an integrated energy-water resource plan with regionalized environmental carrying capacity as constraints is a desideratum to settle this puzzle. Hence, in this section, firstly possible measures to cut down (or avoid) water consumption will be discussed. Then, an alternative scenario will be proposed to guide the sustainable energy development in these coal power base provinces.

#### *5.1. Water Conservation Measures*

#### 5.1.1. Downsizing Coal Power Capacity

The most effective measure to cope with water resource crisis caused by power generation is cutting down the scale of coal power capacity in western provinces. In other words, an alternative power plan is needed. The following strategies can be employed in developing the power sector plan:

x Reducing electric power demand by active energy efficiency efforts. Energy efficiency has been regarded as the fifth energy source besides coal, oil, gas and hydropower. Worldwide experience has also clearly demonstrated the efficacy of energy efficiency in optimizing energy system. We estimate that with active energy efficiency efforts, the demand growth for electric power can be slowed down by 2%–3% and results in energy conservation at 200– 300 TWh annually. The energy efficiency potential into 2020 by various active efforts is shown in Table 7.


**Table 7.** The energy efficiency potential of active efforts into 2020.


### 5.1.2. Saving Water by Improving the Cooling System

The cooling system consumes most of water in the power generation process. Therefore, another priority of water conservation is to improve the cooling system in coal power plants. In the existing coal power fleet, these plants with advanced closed-loop water cooling system perform as effectively as those with air-cooled system in terms of the comprehensive water consumption rate while enjoying super energy efficiency advantage. Here, an important measure is to raise the technical threshold of new coal power plants and require that all the newly-constructed coal power plants perform better in their water consumption than the existing records. For existing plants, technical retrofitting can be implemented in those plants with below than average water efficiency performance.

#### 5.1.3. Saving Water in Other Links

The demand on water quality in the other links of power plants is not as strict as in the cooling system. For example, treated wastewater, instead of fresh water, can be used in the desulfurization system and the coal yard. Use of nontraditional water sources, such as secondary-treated municipal wastewater, provides an option to reduce freshwater usage in thermal power production [41]. In the subsequent subsection, concrete water conservation measures are proposed from many links in the generation process.


### *5.2. An Alternative Water Consumption Scenario*

In the alternative water consumption scenario, with energy efficiency efforts, electricity demand is projected to drop from 7705.5 TWh to 7560 TWh. In addition, with more clean and sustainable energy sources, the demand for thermal power is reduced by almost 100 GW, as shown in Table 8.


**Table 8.** Alternative power demand and power planning.

Due to technological advances and structural optimization, the comprehensive water consumption rate could be cut down by a large extent in the alternative scenario. Our estimate is that the water consumption rate could be cut down by 30% from the existing level. In addition, we project that more air-cooled units would be built. The details of the alternative scenario are reported in Table 9.


**Table 9.** Alternative water consumption in coal power base provinces.

In the alternative scenario, planned coal-fired generation capacity in these provinces would be 13 GW lower than in the BAU scenario. Also, the comprehensive water consumption rate of the closed-loop cooling system would be lowered to 1.27 m3 /MWh. The water consumption by coal power in these provinces will be 1212 million m3 , with only a slight increase relative to 2012 level. In this way, the envisioned water crisis caused by the electric power industry in these water-deprived provinces could possibly be avoided. However, we should not be too optimistic about it. Great risk exists in the implementation of water conservation measures and their actual effects.

#### **6. Concluding Remarks**

Coal power is an inevitable choice for meeting the increasing electric power demand in China. Considering the ever worsening atmospheric pollution, the Chinese Government has to adhere to the path of developing large-scale coal power bases in western provinces. However, the analysis presented in this paper clearly indicates that there will be furious water-energy conflicts in the development of coal bases, and water resource constraints will seriously restrict their development. An integrated planning of energy and water resources which takes regionalized environmental carrying capacity as the constraint is a final resort to this sustainable development puzzle. Several concrete water conservation measures are proposed to address the water crisis in China's coal power bases.

Certainly, our study is suffering from some limitations. For example, the perspective employed in the study is water resource constraint. Other important factors, such as the deployment cost of new cooling system and the retrofitting cost of existing cooling system, the economic appraisal of water conservation in links other than cooling system, are not addressed in the study. Water issue is only projected to worsen in the future, as a consequence of climate change. Therefore, further and more in-depth analysis on the issues presented here is needed to provide guidance for Chinese government and other stakeholders.

#### **Acknowledgments**

The authors would like to thank the anonymous reviewers for their useful comments and suggestions. The work reported in the paper is funded by Beijing Higher Education Young Elite Teacher Project (YETP0707) and the Fundamental Research Funds for the Central Universities.

#### **Author Contributions**

Jiahai Yuan contributed to the research idea and the framework of this study. Other authors contributed equally to the study.

#### **Appendix**


**Table A1.** Energy efficiency and water efficiency statistics on coal-fired power plants in China, 2012.


**Table A1.** *Cont.*


**Table A1.** *Cont.*


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**Table A1.** *Cont.*

### **Conflicts of Interest**

The authors declare no conflict of interest.

#### **References**


