Categorising virtual water transfers through China's electric power sector

Water consumption in thermoelectric and hydropower plants in China increased from 1.6 and 6.1 billion m3, respectively, to 3.8 and 14.6 billion m3 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 m3, whilst virtual water in electricity used by industries (hereinafter referred to as VWEI) increased from 5.82 to 11.13 billion m3. 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 m3 to 7.19 and 20.33 billion m3, 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

Life-cycle water uses for energy consumption of Chinese households from 2002 to 2015

China's household energy demands' life-cycle water uses from 2002 to 2015 are quantified with an Input-Output analysis disaggregating rural and urban impacts. 9.73 and 1.60 km3 of water was withdrawn and consumed respectively in the life cycle of Chinese household energy demands in 2015, which was dominated by power and heat uses. An average urbanite's household energy uses, including coal, gas, petroleum products, power and heat, require about four times of life-cycle water uses than its rural counterpart. Among all upstream sectors, while agricultural sectors accounted for the largest shares for all energy uses, oil and gas extraction made significant contributions to petroleum products and gas consumption. A Structural Decomposition Analysis is conducted to disentangle the impacts of four driving factors, i.e. population, demand, economic structure and technology. Population change reduced energy consumption's life-cycle water use for rural households but increased that for urban households. Each economic sector's water intensity decreases, which represent technology advancement, played the dominant role curbing household energy consumption's life-cycle water uses. While power and heat dominates the household energy use profile, urbanization is accompanied by household consumption shifting from coal to gas and petroleum products. In order to reduce household energy consumption's impacts and reliance on water resources, it is imperative to reduce energy production'swater use by adopting water-saving technologies, such as air cooling, as well as to reduce upstream sectors' water intensities, such as by promoting drip irrigation

Future conflicts of water demands and availability in Chinaâs power sector

Electricity use is indispensable for almost every aspect of modern human society, from agricultural and industrial production to household consumption. It is increasingly recognized that, besides hydropower, water resources are also required for thermoelectric power production that provides the majority of the worldâs electricity use. Therefore, water security can have serious impacts on electricity security. Electric power curtailments caused by water-related issues have been reported all around the world. China, the world largest electric power producer, faces pronounced challenges in this respect as its electric power sector heavily relies on coal-fired power plants that are located at inland water ways. Water shortages may induce substantial cost for under-serving electricity to its large population and fast growing economy. However, such risks, including their magnitudes and spatiotemporal characteristics, are not well understood, especially under future climate change. Against this backdrop, this dissertation, for the first time, examines water shortage risks facing Chinaâs electric power sector on plant-level and monthly bases within a comprehensive framework. It first develops a comprehensive inventory of plant-level water-using technology dataset and, based on which, quantifies the electric power sectorâs water demands in China. Water availability is then simulated with a calibrated hydrological model that incorporates human interventions during the current period (1984-2014) and future period 2050s (2035-2065) under two carbon emission scenarios RCP 2.6 and 8.5. Spatial and temporal water risks can be identified where water availability falls short of water demands. Finally, using the concept of virtual water within the Input-Output framework, water uses for electric power productions are attributed to different end users whose electricity use could be disrupted should those above-identified risks arise. From 2000 to 2015, water withdrawal and consumption in Chinaâs electric power sector, excluding hydropower, have increased from 40.75 and 1.25 billion m3, respectively, to 124.06 and 4.86 billion m3. Freshwater use withdrawal and consumption are projected to exceed 280 and 15 billion m3 respectively by 2050 if China does not implement any new policies, up from current levels of 65.2 and 4.64 billion m3 (2014). At a regional level, central and eastern China account for the majority of the power sectorâs water withdrawals because open-loop cooling systems are widely adopted, while water consumption is significantly higher in the current dry northern regions because closed-loop cooling systems are more popular. It is found that around 10% of Chinaâs coal-fired power capacity is facing low flow water risks from July to October, and 20% the rest of the year. Particularly in the north, 40% to 60% of its regional coal-fired power capacity is at risks of not having enough water for cooling purposes from February to June. Under climate change, available water in the river system is expected to increase significantly in the current dry north and decrease significantly in the northwest and slightly in the south, which is expected to alleviate the low flow water risks facing Chinaâs coal power plants except in the northwest Inland River Basin. In the east and south, if their growing electricity demands continue depending on coal, increasing utilization rate of coal power facilities can lead to the increase of demand-driven water shortage risks. Lastly, this dissertation includes water consumption by both thermoelectric and hydropower plants to reveal the virtual water flows from power producers to consumers using Multi-Regional Input-Output analysis. From 2002 to 2012, the share virtual water embodied in the final consumption of electricity, e.g. household, increased from 24.6% to 39.8%. 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.</p

Unveiling Economic Co-Benefits of Virtual Water Trades: An Empirical Analysis on China’s JingJinJi Megalopolis

The development of metropolitan cities inevitably relies on natural resources beyond their boundary through trade of materials and products, particularly within the same urban agglomeration. Meanwhile trade facilitates the optimization of resource allocations under scarcity, among cities and sectors, and therefore generates economic gains. This study constructs an economic evaluation model combining a Multi-Regional Input-Output model and a Data Envelopment Analysis (DEA) to quantify the economic impacts of virtual water trades among the 13 cities in the JingJinJi region (China national capital area), one of the most water-scarce regions in China. We found that the total virtual water trade among the 13 cities amounted to 927 million m3 in 2012, among which agricultural sectors contributed 90% while the industrial sector and service sector together made up the remaining 10%. While Beijing and Tianjin are the main virtual water importers, importing respectively 300.48 and 226.92 million m3 in 2012, Shijiazhuang was the largest virtual water exporter, exporting 173.29 million m3 virtual water in the same year. Due to their more advanced economic conditions, Beijing and Tianjin also have the highest shadow prices of water, at respectively 912.21 and 831.86 CNY per m3, compared to a range of 79.31 to 263.03 CNY per m3 in cities in Hebei. Virtual water flows from cities in Hebei to Beijing and Tianjin thus generate economic gains. It is estimated that virtual water trades in the JingJinJi region have generated a net economic gain of 403.62 billion CNY in 2012, particularly owing to trades of agricultural products from Shijiazhuang to Beijing and Tianjin

Future conflicts of water demands and availability in China’s power sector

Electricity use is indispensable for almost every aspect of modern human society, from agricultural and industrial production to household consumption. It is increasingly recognized that, besides hydropower, water resources are also required for thermoelectric power production that provides the majority of the world’s electricity use. Therefore, water security can have serious impacts on electricity security. Electric power curtailments caused by water-related issues have been reported all around the world. China, the world largest electric power producer, faces pronounced challenges in this respect as its electric power sector heavily relies on coal-fired power plants that are located at inland water ways. Water shortages may induce substantial cost for under-serving electricity to its large population and fast growing economy. However, such risks, including their magnitudes and spatiotemporal characteristics, are not well understood, especially under future climate change. Against this backdrop, this dissertation, for the first time, examines water shortage risks facing China’s electric power sector on plant-level and monthly bases within a comprehensive framework. It first develops a comprehensive inventory of plant-level water-using technology dataset and, based on which, quantifies the electric power sector’s water demands in China. Water availability is then simulated with a calibrated hydrological model that incorporates human interventions during the current period (1984-2014) and future period 2050s (2035-2065) under two carbon emission scenarios RCP 2.6 and 8.5. Spatial and temporal water risks can be identified where water availability falls short of water demands. Finally, using the concept of virtual water within the Input-Output framework, water uses for electric power productions are attributed to different end users whose electricity use could be disrupted should those above-identified risks arise. From 2000 to 2015, water withdrawal and consumption in China’s electric power sector, excluding hydropower, have increased from 40.75 and 1.25 billion m3, respectively, to 124.06 and 4.86 billion m3. Freshwater use withdrawal and consumption are projected to exceed 280 and 15 billion m3 respectively by 2050 if China does not implement any new policies, up from current levels of 65.2 and 4.64 billion m3 (2014). At a regional level, central and eastern China account for the majority of the power sector’s water withdrawals because open-loop cooling systems are widely adopted, while water consumption is significantly higher in the current dry northern regions because closed-loop cooling systems are more popular. It is found that around 10% of China’s coal-fired power capacity is facing low flow water risks from July to October, and 20% the rest of the year. Particularly in the north, 40% to 60% of its regional coal-fired power capacity is at risks of not having enough water for cooling purposes from February to June. Under climate change, available water in the river system is expected to increase significantly in the current dry north and decrease significantly in the northwest and slightly in the south, which is expected to alleviate the low flow water risks facing China’s coal power plants except in the northwest Inland River Basin. In the east and south, if their growing electricity demands continue depending on coal, increasing utilization rate of coal power facilities can lead to the increase of demand-driven water shortage risks. Lastly, this dissertation includes water consumption by both thermoelectric and hydropower plants to reveal the virtual water flows from power producers to consumers using Multi-Regional Input-Output analysis. From 2002 to 2012, the share virtual water embodied in the final consumption of electricity, e.g. household, increased from 24.6% to 39.8%. 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.</p

Global food trade alleviates transgressions of planetary boundaries at the national scale

Summary: Food systems are among the leading causes for transgression of planetary boundaries globally, which define the safe operating space for humanity. We quantify unsustainable environmental impacts of food systems, indicated by the transgression of national-scale planetary boundaries (i.e., the safe operating space for food production in each country), from both production and consumption perspectives of 189 countries/regions around the world. A multi-regional input-output model is used to map the global transfers of the national-scale transgression of planetary boundaries, including freshwater use, land change, and biogeochemical flows (nitrogen and phosphorus). Our results show that China is a major global unsustainable water and nitrogen exporter and an unstable land and phosphorus importer. This means that water and nitrogen uses in China are used to support food demands in other countries, and food consumption in China requires unsustainable land and phosphorus uses elsewhere. In contrast, the US is a major exporter of unsustainable water, land, and nitrogen uses but only an importer of unsustainable phosphorus for food consumption. Globally, compared to a counterfactual scenario where there is no food trade among any countries, food trade saves massive transgressions of planetary boundaries (270 km3 of water, 18 million tons of nitrogen, 7 million tons of phosphorus, and 5,431 million km2 of land). Alleviation of national-scale planetary boundary transgression has been achieved primarily in the US, China, Saudi Arabia, etc., while aggravation was incurred in Pakistan, Australia, Argentina, and so forth

Demographic Scenarios of Future Environmental Footprints of Healthy Diets in China

Dietary improvement not only benefits human health conditions, but also offers the potential to reduce the human food system&rsquo;s environmental impact. With the world&rsquo;s largest population and people&rsquo;s bourgeoning lifestyle, China&rsquo;s food system is set to impose increasing pressures on the environment. We evaluated the minimum environmental footprints, including carbon footprint (CF), water footprint (WF) and ecological footprint (EF), of China&rsquo;s food systems into 2100. The minimum footprints of healthy eating are informative to policymakers when setting the environmental constraints for food systems. The results demonstrate that the minimum CF, WF and EF all increase in the near future and peak around 2030 to 2035, under different population scenarios. After the peak, population decline and aging result in decreasing trends of all environmental footprints until 2100. Considering age-gender specific nutritional needs, the food demands of teenagers in the 14&ndash;17 year group require the largest environmental footprints across the three indicators. Moreover, men&rsquo;s nutritional needs also lead to larger environmental footprints than women&rsquo;s across all age groups. By 2100, the minimum CF, WF and EF associated with China&rsquo;s food systems range from 616 to 899 million tons, 654 to 953 km3 and 6513 to 9500 billion gm2 respectively under different population scenarios. This study builds a bridge between demography and the environmental footprints of diet and demonstrates that the minimum environmental footprints of diet could vary by up to 46% in 2100 under different demographic scenarios. The results suggest to policymakers that setting the environmental constraints of food systems should be integrated with the planning of a future demographic path

Inter-provincial electricity transmissions’ co-benefit of national water savings in China

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.</p

Capacity estimation based on incremental capacity and Gaussian process regression for retired lithium-ion batteries

Fast capacity estimation for retired batteries is necessary when batteries are recycled for echelon utilization. Here, a fast capacity estimation method is proposed for retired LiFePO4 battery. First, a full survey of battery pack and cells degradation after a long period of service is studied. Then the filtered ICA is used to study degradation variation phenomenon of retired batteries, the relationship between IC curve feature and remaining capacity was studied. Finally, a fast capacity estimation using incremental capacity and Gaussian process regression is proposed. Our results show high efficiency and accuracy of the proposed method