Regional water footprints of potential biofuel production in China

Abstract

BackgroundDevelopment of biofuels is considered as one of the important ways to replace conventional fossil energy and mitigate climate change. However, rapid increase of biofuel production could cause other environmental concerns in China such as water stress. This study is intended to evaluate the life-cycle water footprints (WF) of biofuels derived from several potential non-edible feedstocks including cassava, sweet sorghum, and Jatropha curcas in China. Different water footprint types including blue water, green water, and grey water are considered in this study. Based on the estimated WF, water deprivation impact and water stress degree on local water environment are further analyzed for different regions in China.ResultsOn the basis of the feedstock resource availability, sweet sorghum, cassava, and Jatropha curcas seeds are considered as the likely feedstocks for biofuel production in China. The water footprint results show that the feedstock growth is the most water footprint intensive process, while the biofuel conversion and transportation contribute little to total water footprints. Water footprints vary significantly by region with climate and soil variations. The life-cycle water footprints of cassava ethanol, sweet sorghum ethanol, and Jatropha curcas seeds biodiesel were estimated to be 73.9–222.2, 115.9–210.4, and 64.7–182.3 L of water per MJ of biofuel, respectively. Grey water footprint dominates the life-cycle water footprint for each type of the biofuels. Development of biofuels without careful water resource management will exert significant impacts on local water resources. The water resource impacts vary significantly among regions. For example, based on blue and grey water consumption, Gansu province in China will suffer much higher water stress than other regions do due to limited available water resources and large amount of fertilizer use in that province. In term of blue water, Shandong province is shown with the most severe water stress issue, followed by Gansu province, which is attributed to the limited water resources in both provinces.ConclusionsBy considering feedstock resource distribution, biofuel production potentials, and estimated water footprints, this study provides insight into the impact of biofuel production on the local water environment in China. Biofuel development policies need to be carefully designed for the sustainable development of biofuels in China.

GIS- Based Screening Model of Coastal City Karachi for Plantation of Biofuel Source

“…However, any areas shown in white are considered least suitable with slope amount more than 30°. Surface slopes greater than 30 degrees directly influence the soil erosion, sediments transportation, irrigation and drainage patterns 23 . A land with slope greater than 25 or 30 degrees is usually given the least priority as it is a cause of water loss and soil erosion.…”

Assessment of Sweet Sorghum-Based Ethanol Potential in China within the Water–Energy–Food Nexus Framework

“…The life cycle of sweet sorghum-based ethanol includes five stages: sweet sorghum planting and harvesting stage, sweet sorghum transport stage, ethanol production stage, ethanol transport and distribution stage, and ethanol combustion stage. The water consumption of every life cycle stage was analyzed, except for the two transport stages and the ethanol combustion stage because the quantity of water consumption in these three stages represented less than 1% of the total water consumption [16,17]. The GHG emissions and net energy gain were assessed by tracking the material and energy flow in all stages.…”

“…Recent studies showed that inappropriate development planning of biofuels may cause conflicts with water and food [14]. Increased biofuel demand would push up water use, and the low water efficiency of developing bio-ethanol on the marginal lands could aggravate water consumption [15][16][17]. Besides, planting energy crops on the cultivated lands may improve energy supply, but it also results in less cultivated lands for food planting and causes risks to food security [18].…”

Water Footprint and Water Pinch Analysis in Ethanol Industrial Production for Water Management

“…They defined the WF of a product as the total volume of fresh water consumed across the entire value chain of production. Previous studies of WF have investigated the water footprints of ethanol production [19][20][21][22][23] but most of them focused on calculating the WFs of feedstocks; few have reported the WF at an industrial scale. In this study, the WF of ethanol production on an industrial scale was calculated and used as an evaluation indicator for water integration.…”