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Interprovincial electricity transmissions have been utilised in China to overcome the country's imbalanced social-economic development and resource endowments. A bottom-up technology-based model is adopted to estimate water uses in electricity-exporting provinces to produce the transmitted electricity as well as opportunistic water savings in the receiving provinces. The results highlight that, in 2014, on a national scale, electricity transmissions generated co-benefit of saving 20.1 billion m³ of water nationally due to the electric power sector's water productivity differences in the exporting and importing provinces. Taking regional water stresses into account, 10.98 billion m³ of national scarce water saving is realized through electricity transmissions. Moreover, electricity transmissions by China's proposed 12 future transmission lines are expected to use additional 3.22 billion m³ of water in the electricity-exporting provinces. As more water-intensive technologies, e.g. open-loop cooling, are more commonly utilised in the electricity-receiving provinces, a total amount of 16.97 billion m³ of water use will be avoided nationally. Water-use efficiency for power production should be improved in all regions. Transmitted power imports should still be encouraged in water-scarce regions to alleviate their water stresses while power exports should be shifted away from water-stressed regions to water-abundant ones. Energy transformation by utilising gas-fired capacity and hydropower in water-abundant Southern China could be advanced. [ABSTRACT FROM AUTHOR]

With a Multi-Regional Input-Output analysis, this study for the first time quantifies China's final electricity demands' life-cycle impacts on water quality using the indicator Grey Water Footprint (GWF). China's Grey Water Footprint for Final Power Demands (GWFP) amounts to 37.54 billion m³ in 2010, which is the highest in the north, east and central regions. Regarding the upstream sectoral contributions on a national scale, Coal Mining and Dressing, whose GWF is decided mainly by Chemical Oxygen Demand (COD) and petroleum, and Agriculture sector, whose GWF is decided by total nitrogen discharged, contribute the largest shares of 32.40% and 23.24%, respectively. 22.28 billion m³ of GWFP is transferred across provincial boundaries as virtual grey water embodied in electricity transmissions and trades of the power sector's upstream supplies. Electric power demands in coastal provinces induce water pollution in inland provinces. For example, 1.38, 1.07 and 1.06 billion m³ of GWF in Shanxi, Inner Mongolia, and Henan, respectively, are generated to fulfill final power demands in Shandong, Jilin and Shandong. Findings in this study are significant in helping policymakers recognize and mitigate final power demands' life-cycle adverse impacts on water quality. Moreover, insights of the inter-provincial virtual grey water transfers induced by power demands enable further discussions on burden sharing and compensation in terms of power demand management and water pollution controls. [ABSTRACT FROM AUTHOR]

Grey water footprint (GWF) accounting has previously been conducted at the global level using a bottom-up approach but lacking detailed industrial information. Here we applied a multi-region input-output approach based on the World Input-Output Database (WIOD) to quantify global GWF of 40 countries/regions with 35 economic sectors. The GWF from both the production perspective (GWFP), and the consumption perspective (GWFC) are quantified. The results show that the global GWFP/GWFC was 1507.9 km3 in 2009. Except for the "Agriculture, Hunting, Forestry and Fishing" sector, the industrial sectors with the largest GWFC were "Food, Beverages and Tobacco", "Construction", "Chemicals and Chemical Products", and "Textiles and Textile Products". The BRIC countries (Brazil, Russia, India, China) had a larger GWFP than their GWFC, which accounted for over half of global GWFP (53.6%), and their GWFP was mainly generated from the production of domestic final demand. In contrast, the OECD29 and EU27 groups of countries i.e. the country groups consisting mainly of economically advanced nations, had larger GWFC than their GWFP. Overall, the OECD29 and EU27 outsourced 134.8 km3 and 64.4 km3 of their grey water respectively, mostly to large newly advanced economies such as the BRIC group of countries, which, in turn, were collectively outsourcing 112 km3 of grey water. Quantitative approaches are thus suggested for development, aimed at shared responsibility for water pollutant discharge among poor exporters and wealthy consumers. • Global Grey Water Footprint (GWF) was quantified from production and consumption perspectives. • Multi-region input-output approach was applied to account for GWF of 40 countries/regions. • Global GWF was 1507.9 km3 in 2009. • BRIC countries accounted for 53.6% of the global GWF from production perspective. • OECD29 and EU27 outsourced 134.8 and 64.4 km3 of their grey water, respectively. [ABSTRACT FROM AUTHOR]

Highlights • Water for energy sector in China's two biggest megalopolises was analyzed. • Energy sector in Jing-Jin-Ji had 2.41 km3 of water withdrawal footprint in 2010. • Energy sector in Yangtze Delta had 9.59 km3 of water withdrawal footprint in 2010. • Water consumption footprint was 848.06 and 973.91million m3 respectively. • Jing-Jin-Ji had much larger external water footprint than Yangtze Delta. Abstract Using a consumption-based Multi-Regional Input-Output (MRIO) model, we investigate the distinctive characteristics, self-efficiency or external dependency, of energy demand's water footprint in China's two biggest and fastest developing megalopolises. We find that energy demand water footprint in the Jing-Jin-Ji and the Yangtze Delta amounted to 2.41 and 9.59 billion m³of water withdrawal respectively in 2010, of which 848.06 and 973.91 million m³was consumed. Among all energy products, electricity contributed the largest share to the energy sector's water footprint in both regions. The sectoral distribution of water footprint in the upstream supply chain differed by region. Most significantly, the agricultural sector accounted for more than 30% of water consumption footprint. In addition to water used locally, final energy demands in these two regions induced external water footprint beyond their administrative boundaries. The Jing-Jin-Ji region's energy sector had a smaller water footprint compared to the water-abundant Yangtze Delta region. However, external water footprint occupied a larger proportion in the former. Such divergence can be attributed to the distinctive water endowments and water-using technologies utilized in their respective energy sectors. Bespoke urban governance and policies tailored to local resource and technology portfolios are recommended for different urban agglomeration energy and water flows. [ABSTRACT FROM AUTHOR]

Abstract In China, vehicle electrification is developed as a way to decouple people's increasing demand for on-road transport and concerns for adverse environmental impacts. Replacing conventional fuel with electricity not only yields impacts on air pollution and greenhouse gas emissions, but also on water resources. This study addresses such impacts for the first time. Based on China's existing plans, we expect China's future electric vehicles will grow from 5 million in 2020 to 80 million in 2030, requiring 47 to 335 TWh of electricity supplies respectively. In order to produce such amount of electricity, under a baseline scenario, 42.60 million m³ and 1.09 billion m³ of water is projected to be consumed and withdrawn in 2020, respectively, which are expected to grow to 324.45 million and 8.56 billion m³ in 2030. Deploying renewable energies offers considerable potentials cutting electric vehicles' indirect impacts on water resources by more than 20% as their productions require less water inputs than coal-fired power plants. Changing cooling technologies' impacts differ by regions, increasing water consumption in southern regions while reducing water consumption in the north. However, if water consumption avoided from avoiding conventional fuel productions is taken into account, compared to the counterfactual scenario where the same number of traditional vehicles will be deployed, future electric vehicles in China will lead to net decreases of 19.3, 64.3 and 89.7 million m³ of scarce water consumption nationally under baseline, high renewable and cooling technology change scenarios in the electric power sector respectively. Highlights • Electric vehicle (EV) amount is expected to reach 80 million in China by 2030. • From 2020 to 2030, electricity demand by China's EVs will increase by 6 times to be 335 TWh. • 8.56 billion m³ of water will be withdrawn by electricity generation for EV in 2030. • EV rising can save water in North China by avoiding oil production. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Both water depletion and pollution by coal-fired power generation are quantified. • Petroleum pollutant determines the life cycle grey water footprint. • Water pollution mostly occurs in the fuel supply sector. • The grey water footprint was reduced by 49% from 2002 to 2012. Abstract In the present study, both water depletion and degradation in the life cycle of power generation at coal-fired power plants in China are quantified using a mixed-unit input-output model. National life cycle Withdrawal, Blue and Grey water footprint (WF) of thermal power production in China are estimated to be 35.46, 2.14 and 17.67 m3 per MWh of electricity produced, respectively. Those three types of life cycle WFs experienced significant reductions from 2002 to 2012 due to improved technologies such as water saving and wastewater treatment. Although Chemical Oxygen Demand (COD) pollutant had the largest discharge amount in the life cycle process of electricity generation, petroleum pollutant that was mostly discharged from coal production determined the Grey WF because of its lower permissible concentration. The spatial distribution of scarce WFs, incorporating regional water stresses, is also studied at the provincial level to identify the impacts of thermal power generation on regional water scarcities. Scarce water consumption was concentrated in northern China while scarce water was predominantly withdrawn in eastern China. [ABSTRACT FROM AUTHOR]

Water consumption in thermoelectric and hydropower plants in China increased from 1.6 and 6.1 billion m 3 , respectively, to 3.8 and 14.6 billion m 3 from 2002 to 2010. Using the concept of virtual water, we attribute to different electricity users the total water consumption by the electric power sector. From 2002 to 2010, virtual water embodied in the final consumption of electricity (hereinafter referred to as VWEF) increased from 1.90 to 7.35 billion m 3 , whilst virtual water in electricity used by industries (hereinafter referred to as VWEI) increased from 5.82 to 11.13 billion m 3 . The inter-provincial virtual water trades as a result of spatial mismatch of electricity production and consumption are quantified. Nearly half (47.5% in 2010) of the physical water inputs into the power sector were virtually transferred across provincial boundaries in the form of virtual water embodied in the electricity produced, mainly from provinces in northeast, central and south China to those in east and north China. Until 2030, VWEF and VWEI are likely to increase from 5.27 and 14.89 billion m 3 to 7.19 and 20.33 billion m 3 , respectively. Climate change mitigation and water conservation measures in the power sector may help to relieve the regional pressures on water resources imposed by the power sector. [ABSTRACT FROM AUTHOR]

We quantify the current water use of China’s thermoelectric power sector with plant-level data. We also quantify the future implications for cooling water use of different energy supply scenarios at both a regional and national levels. Within China, water withdrawal and consumption are projected to exceed 280 and 15 billion m 3 respectively by 2050 if China does not implement any new policies, up from current levels of 65.2 and 4.64 billion m 3 . Improving energy efficiency or transforming the energy infrastructure to renewable, or low-carbon, sources provides the opportunity to reduce water use by over 50%. At a regional level, central and eastern China account for the majority of the power sector’s water withdrawals, but water consumption is projected to increase in many regions under most scenarios. In high-renewable and low-carbon scenarios, concentrated solar power and inland nuclear power, respectively, constitute the primary fresh water users. Changing cooling technology, from open-loop to closed-loop in the south and from closed-loop to air cooling in the north, curtails the power sector’s water withdrawal considerably while increasing water consumption, particularly in eastern and central China. The power sector’s water use is predicted to exceed the regional industrial water quota under the ‘3 Red Line’ policy in the east under all scenarios, unless cooling technology change is facilitated. The industrial water quota is also likely to be violated in the central and the northern regions under a baseline scenario. Moreover, in line with electricity production, the power sector’s water use peaks in the winter when water availability is lowest. Water-for-energy is a highly contextual issue – a better understanding of its spatio-temporal characteristics is therefore critical for development of policies for sustainable cooling water use in the power sector. [ABSTRACT FROM AUTHOR]

The North China Grid has the highest proportion of fossil fuel-based electricity generation in China and also suffers from severe water scarcity issues. This study uses a multi-objective optimization model to explore future configurations of generating and cooling technologies of the electric power sector in the North China Grid subject to constraints imposed by existing policies on water conservation and carbon reduction in 2030. Our findings highlight that the current carbon reduction commitments of China do not have significant impacts on the North China Grid's electric power sector development while policies in the water sector generate much larger impacts. Imposing water constraint according to the 'Three Red Line' Policy requires increasing utilization of wind power and air cooling systems, which simultaneously increases economic cost and carbon emissions compared to the business as usual scenario. Imposing enhanced carbon emission and water consumption constraints reap the co-benefits of carbon reduction and water conservation by increasing the proportion of solar PV generation to 8.21%, which increases the unit electricity cost from RMB 0.82 per kWh to RMB 1.37 per kWh. In 2030, electricity generation in the North China Grid generates 1599.88 to 1690.89 million tons (Mt) of carbon emissions under different scenarios whereas imposing water constraint reduces water consumption from 3.34 billion m3 to 1.94 billion m3. Unlabelled Image • China's current carbon targets do not affect the development of the North China Grid. • Water sector policies have much larger impacts on the North China Grid. • Capping water use increases carbon emissions from the North China Grid. • Imposing both water and carbon constraints can realize co-benefits but at higher costs. [ABSTRACT FROM AUTHOR]

Urbanization is accompanied by growing household consumption and changing consumption patterns, with both having impacts on the life-cycle water pollution generated. This study uses the indicator of grey water footprint (GWF) within an Input-Output framework to examine the decadal change from 2002 to 2017 of the life-cycle water pollution change for household consumption in China, where rapid urbanization has particularly posed looming environmental challenges. Against the background of enlarging inequality, the results also shed light on the impacts of households within different income groups. From 2002 to 2017, GWF required by urban household consumption has increased significantly from 1586 to 2195 km3 while that for rural households have decreased slightly from 1139 to 964 km3 during the same period. Total Nitrogen required the largest GWF throughout the whole period and throughout all different income groups. Food consumption dominated the GWF for household consumption. However, the share of GWF for food consumption decreases with income increases, from 83% for extremely poor rural households to 71% for very rich urban households in 2012. Urbanites on average require higher GWF for their consumption than their rural counterparts. An average person from the highest income rural households required 2033 m3 GWF for household consumption, which is higher than a person from a very poor urban household (1685 m3) but lower than that of a person from poor urban household (2149 m3). While household consumption volume increase has been the primary driver for GWF increase, pollution intensity reduction has offset such impacts. Household consumption pattern change's impacts differ by household income and by pollutant considered. Unlabelled Image • This study assesses the household consumption's GWF in China from 2002 to 2017. • Total nitrogen determines the grey water footprint (GWF) of household consumption. • The change of household consumption's GWF was greatly driven by increasing consumption expenditure. • The increasing GWF from the poor to the rich is retarded by the changing consumption pattern. [ABSTRACT FROM AUTHOR]

Substantial amounts of greenhouse gas (GHG) emissions generated at urban wastewater treatment plants (WWTP) are gaining increasing appreciation. Improving upon the commonly used Process-Based Life-Cycle Analysis (PLCA) and Environmentally-Extended Life-Cycle Analysis (EIO-LCA) models, we construct a Hybrid Life Cycle Analysis (HLCA) model and quantify both direct and indirect GHG emissions at the operational stage of WWTPs in Shenzhen, one of the fastest urbanizing cities in the world. Data are collected from 26 wastewater treatment plants in Shenzhen, out of all 32, covering 5 commonly used wastewater treatment technologies in China, i.e. Sequencing Batch Reactor, Oxidation Ditch, Biological Filter, AAO-MBR and AAO. The results show that WWTPs using AAO-MBR technology have the highest GHG emission intensity, averaging 0.79 tons per m3, primarily due to its large electricity intensity required. WWTPs using other technologies emit 0.27 to 0.39 tons of GHGs per m3 of wastewater treated. GHG emissions associated with electricity use occupy the largest share, ranging from 65 to 75%. Therefore, transforming the energy structure of the electric power sector to low-carbon sources can reduce WWTPs operational GHG emissions. In total, GHG emissions from Shenzhen's urban wastewater sector have increased from below 0.5 million tons in 2012 to over 0.6 million tons in 2017. Inter-model comparison shows that EIO-LCA substantially underestimates the urban wastewater sector's GHG emissions using the water sector's average parameters while PLCA also results in minor underestimations due the omission of indirect emissions in the production stage of chemicals and other material inputs. Unlabelled Image • Hybrid Life Cycle analysis (HLCA) is constructed to evaluate WWTP's GHG emissions. • GHG from WWTPs in Shenzhen grew from below 0.5 Mt. in 2012 to over 0.6 Mt. in 2017. • Upstream electricity production occupies 65 to 75% of the operational GHG of WWTPs. • AAO-MBR has the highest GHG emission intensity, twice as that of others. • Process-based and EIO LCA both underestimates WWTP's operational GHG emissions. [ABSTRACT FROM AUTHOR]

• The water scarcity footprint enables meaningful spatial comparisons of water impact. • We compared the water scarcity footprint of energy demand for 6 Chinese megacities. • Our results highlight the impacts of energy demand extend beyond the city boundary. • The water scarcity footprint of northern Chinese megacities is higher than southern. • Fossil fuel processing in northern China contributes to scarce water consumption. Water is required throughout the life-cycle processes of energy production to meet the growing energy demands in China's megacities. However, the spatially explicit impact on water scarcity both inside and outside the megacity boundaries from megacities' energy demands remains unknown. We quantified and compared the water footprint and water scarcity footprint for final energy demand (WFE and WSFE) in China's megacities from a consumption perspective. Six acknowledged megacities, i.e. Beijing, Tianjin, Shanghai, Chongqing, Shenzhen and Guangzhou, were evaluated with an extended multi-region input–output model. The results showed that these megacities were endowed with only 2.60% of the national available water resources, but their WFE (WSFE) made up nearly 14.00% (13.50%) of the national total. The megacities located in Northern China generated a larger WSFE in their WFE than the cities in Southern China. Energy demands in these megacities were heavily dependent on scarce water sourced from beyond their administrative boundaries, together importing 84.10% of WSFE from elsewhere. Electricity demand dominated the volumetric water consumption, representing 52.00% of the WFE. The distribution was different for scarce water consumption, with coal demand generating 34.00% of total WSFE, followed by electricity (31.00%) and petroleum (26.00%). Although Northern China is faced with dire water scarcity, its scarce water is still being predominantly outsourced to support energy demands in both Northern and Southern megacities, mainly due to their coal and petroleum reserves. Location-specific pathways and foci should be applied for different megacities to decouple their energy demands and their scarce water consumption. [ABSTRACT FROM AUTHOR]

Solar energy has expanded rapidly in recent years, and China is the largest market in terms of installed capacity. With the aim of achieving carbon neutrality by 2060, solar power will play an increasingly important role in China. However, like many other countries, the low energy density of solar photovoltaics is one of the major drawbacks of its further development. The emergence of floating photovoltaic systems (FPV) can not only break this threshold but also generate a series of cobenefits from a brand-new energy-land-water nexus perspective. Using a GIS-MCDA model, an evaporation model, combined with a cost-benefit analysis, this paper estimates the development potential of FPV in China, and its energy-land-water cobenefits are further analyzed. Moreover, to reveal the current land constraint for developing solar photovoltaics in China, the potential of traditional terrestrial solar photovoltaics has also been evaluated. The results show that the potential installed capacity of FPV in China can reach 705.2 GW–862.6 GW with an annual 1164.9 TWh to 1423.8 TWh of potential power output, and most potential FPV stations can obtain positive financial returns. The annual water evaporation reduction is approximately 5.8 km3. In the meantime, around 7117.3 km2 of the land could be conserved, which would alleviate the land constraint for terrestrial solar photovoltaic systems, especially in the highly urbanized eastern and southern coastal areas in China. [ABSTRACT FROM AUTHOR]

With the proliferation of electric vehicles (EV), large amounts of retired batteries need to be disposed, which poses emerging waste management challenges. Remanufacturing LIBs with materials recycled from used batteries is gaining increasing appreciation. Its environmental and economic benefits are still controversial and merit further examinations. This paper employs a life-cycle model and a process-based cost model to evaluate the greenhouse gas (GHG) emissions, water consumption, and the related costs of remanufacturing LIBs within the context of China, which is the biggest EV producer. Four types of LIBs, i.e. NCM 111 , NCM 622 , NCM 811 and NCA, and three different recycling methods, i.e. Pyrometallurgical Recycling (PR), Hydrometallurgical Recycling (HR), and Direct Physical Recycling (DPR) are analyzed. The environmental impacts of remanufacturing LIBs are assessed at both national and provincial levels. Results show that compared with manufacturing LIBs with virgin materials, remanufacturing LIBs can significantly reduce GHG emissions, water consumption, and production costs. Among the three recycling methods, DPR has the biggest potentials for reducing GHG emissions, water consumption, and manufacturing costs with 29.27%–38.15%, 30.07%–41.19%, and 25.61%–36.63% reduction, depending on the different types of LIBs. Regarding battery technologies, remanufacturing NCM 111 cell with DPR induces the least negative environmental impacts. Sensitivity analyses show that there are still large profit margins for remanufacturing LIBs with DPR process to bear the used LIB purchase price increase. Potential water-carbon conflicts are demonstrated for developing LIB remanufacturing industry due to different provincial electric power portfolios, which should be considered in future industry planning. [Display omitted] Environmental impacts and economic costs of remanufacturing EV LIBs are evaluated Direct physical recycling cuts manufacturing cost by 25.6–36.6% Direct physical recycling reduces GHG emission by 29.3–38.2% Direct physical recycling reduces water consumption by 30.1–41.2% Provincial analysis reveals potential water-carbon conflicts in remanufacturing LIBs [ABSTRACT FROM AUTHOR]