Sugar cane and sugar beet are used for sugar for human consumption. In the US, maize is used, amongst others,udfor the sweetener High Fructose Maize Syrup (HFMS). Sugar cane, sugar beet and maize are also important forudbio-ethanol production. The growth of crops requires water, a scarce resource. The aim of this study is to assessudthe green, blue and grey water footprint (WF) of sugar, HFMS and ethanol in the main producing countries. Inudaddition, an impact assessment is carried out for sugar cane and beet production in three large river basins: theudDnjepr, Indus and Ganges basins.udThe WF of sweeteners and ethanol depends on crop type, agricultural practice and climate. The WFs of caneudsugar for the main producing countries appear to be 1285 m3/ton for Brazil and 1570 m3/ton for India. Theudweighted global average is 1500 m3/ton (45% green, 49% blue, 6% grey). The WFs of beet sugar for the mainudproducing countries are: 545 m3/ton for France; 580 m3/ton for Germany; 1025 m3/ton for the US; 1430 m3/tonudfor the Russian Federation; and 1900 m3/ton for the Ukraine. The weighted global average is 935 m3/ton (35%udgreen, 49% blue, 16% grey). The average WF of HFMS 55 produced in the US is 720 m3/ton. The globaludaverage WF of HFMS 55 is 1125 m3/ton (50% green, 36% blue, 14% grey). The WF of ethanol from sugar caneudin Brazil is 2450 litre/litre, in the US 2775 litre/litre and in India 2995 litre/litre. The weighted global average isud2855 litre/litre. The WFs of ethanol from sugar beet for the main producers are: 790 litre/litre for France; 845udlitre/litre for Germany; 1290 litre/litre for the US; 2075 litre/litre for the Russian Federation; and 2780 litre/litreudfor the Ukraine. The weighted global average WF is 1355 litre/litre. The WF of ethanol from maize in the US isud1220 litre/litre. The weighted global average WF is 1910 litre/litre.udThe WF of sugar cane contributes to water stress in the Indus and Ganges basins. In the Black Sea area, theudmain problem is pollution from industry and excessive fertilizer application. In that area sugar beet shows audlarge grey WF and is one of the contributors to pollution.udThe results of this study may form the basis for or at least trigger more detailed local impact assessments. Theudstudy shows that the water footprint of sweetener or ethanol strongly depends on its source (which crop) andudorigin (which country, climate and agricultural system). Besides, the relative contributions of the green, blue andudgrey components differ greatly from place to place. The existing differences may be reason to prioritise fromudwhere to best source sweeteners and bio-ethanol. Alternatively, instead of switching to another source or place,udone could analyse the potential for reducing the water footprints in those cases where footprints are currentlyudrelatively high.
展开▼
