The Complex Relationship and Looming Crisis Between Our Thirst For Water and Our Hunger for Energy
May 4th, 2017
Via Global Water Forum, a look at China’s water-energy nexus:
In the last decade, many studies have shed light on the interconnectedness of the provision of water and energy resources. For example, water is an indispensable input for various stages of energy production, particularly as a cooling medium for the operational stage of power generation.1
Yet water-related power production curtailments have been reported all over the world.2,3 This generates a need to identify the potential water risks in the power sector as well as a demand to improve our understanding of the water-for-energy nexus.
This short article summarizes a newly published study4 by researchers from Oxford University addressing the spatio-temporal complexities of water-for-energy nexus in China and highlighting the necessity of incorporating them into the current scientific and policy discussions.
Background to China’s water-for-energy nexus
Water-for-energy is of particular concern in China. Although, the annual supply of renewable water resources per capita in China is low, at only above 2500 m3 per year, equivalent to one quarter of the world average7, the country’s fast developing economy relies heavily on thermoelectric power production, which supplies over 75% of the electricity consumed nationally5. Many plants require water from inland waterways and are thus prone to potential water shortages4, especially under a changing climate.6
In addition, China’s water-for-energy nexus is uneven in its spatiotemporal distribution.8 For instance, while south China is endowed with abundant water resources, north China is characterised by low precipitation, heavy industrialization and dense population. This concentrates water scarcity disproportionately.9 Indeed, the differences are so pronounced that north China is recognised as the region facing the highest water risks for its power production in the world.10
Method
This study uses a bottom-up technology-based model as in Byers et al. (2014)2 to quantify the water use in China’s thermoelectric power sector using 2014 plant-level data compiled from various sources.11,12,13,14 We calculate power plants’ water use by multiplying water intensities, measured as water use per unit of power produced, with the amount of power production.
A power plant’s water intensity is predominantly determined by the cooling system it employs. Similar to Byers et al.2and Zhang et al.16, we identify the cooling technology employed by individual power plants via Google Earth imagery. Three types of cooling systems are mainly used with markedly varied water withdrawal and consumption intensities. Open-loop, closed-loop and air cooling, respectively, use running water, recirculating water and air to dissipate the residual heat from the steam turbines. While open-loop systems demand a substantially higher amount of water withdrawal, closed-loop ones lead to more consumptive water use.15
In our study, water use refers to both water withdrawal and consumption, with water consumption defined as the difference between water withdrawn and that returned to the natural environment.17
To avoid unsustainable future investments, this study also investigates China’s future water-for-energy nexus by 2050 at every five years under different energy scenarios on a regional scale. The scenarios were selected to align with those given by WWF18, which are consistent with existing literature.
Results
The water consumption in China’s thermoelectric power sector in 2014 was plotted based on individual power plants’ water uses (figure 1). We identified four types of water sources used by the power sector: surface water, ground water, reclaimed water, and seawater.
An individual power plant’s water uses of these four types are extrapolated based on reported figures from China Electricity Council.19,20 Apart from seawater, which was solely used along the coast, two areas of high water demand by the power sector are identified: The Huang-Huai-Hai area in north China, and the Yangtze River basin in southeastern China.
In 2011, the Chinese government issued its ‘most stringent’ water policy – ‘Three Red Line’ policy, setting caps on the society’s water use in 2015, 2020, and 2030, at a national and provincial scale. Scholars have foreseen the possibility of China’s power sector violating the national Industrial Water Allowances by 2035.21 However, regional contingencies remain unknown.
Our results show that, in 2030, policy violation at the regional level is most likely to occur in the east, where water is abundant but open-loop cooling technology is prevalent, unless alteration of its cooling system configuration is facilitated (figure 2).
If business continues as usual, non-compliance may also occur in the central region, where water is also intensively withdrawn by power plants equipped with open-loop cooling systems, and in the north, where water scarcity is pressing. Improving energy efficiency and transforming the energy portfolio to low-carbon or renewable technologies may help the power sector comply with the aforementioned policies.
Our study also addressed the intra-annual differences of water use in China’s power sector. Figure 3 indicates that, in line with power demands, water-for-energy peaks over the winter and summer periods.
The fluctuation is especially significant in eastern and central China where their respective highest water withdrawal in December will reach nearly 18 and 14 billion m3 under a baseline scenario by 2050. In light of this, it is worth noting that water availability is especially low in winter periods, potentially posing severe risks to the country’s power provision in the future.
Conclusion
Water-for-energy in China raises new challenges for resource governance, which necessitates novel coping mechanisms. The historical paradigm where water and energy are treated and governed independently, uninformed and unconcerned of the impact one set of policy decisions has on the other, is no longer sustainable.
Further, we have shown that accounting for the water-for-energy nexus solely at a national or annual level is insufficient – in addition, consideration must be given to spatio-temporal variabilities, which may traverse institutional boundaries.
Marginalising the complexities of variation present at a higher resolution, both spatially and temporally, may result in policy violations or governance conflicts, which could impair the credibility of respective institutions and even undermine further efforts. It is thus important to bring such variations into future scientific studies as well as policy decisions.
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Educated at Yale University (Bachelor of Arts - History) and Harvard (Master in Public Policy - International Development), Monty Simus has held a lifelong interest in environmental and conservation issues, primarily as they relate to freshwater scarcity, renewable energy, and national park policy. Working from a water-scarce base in Las Vegas with his wife and son, he is the founder of Water Politics, an organization dedicated to the identification and analysis of geopolitical water issues arising from the world’s growing and vast water deficits, and is also a co-founder of SmartMarkets, an eco-preneurial venture that applies web 2.0 technology and online social networking innovations to motivate energy & water conservation. He previously worked for an independent power producer in Central Asia; co-authored an article appearing in the Summer 2010 issue of the Tulane Environmental Law Journal, titled: “The Water Ethic: The Inexorable Birth Of A Certain Alienable Right”; and authored an article appearing in the inaugural issue of Johns Hopkins University's Global Water Magazine in July 2010 titled: “H2Own: The Water Ethic and an Equitable Market for the Exchange of Individual Water Efficiency Credits.”