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8.4 Results and Discussion

8.4.1 Water footprint of bioethanol production in Thailand

8.4.1.1 Comparative WF of the bioethanol feedstocks
Figure 8.4 shows the comparison of water footprint per ton of bioethanol feedstock

in Thailand including cassava, sugarcane and molasses. Based on the 26 studied provinces, the
total WF for cassava, sugarcane and molasses range between 381 – 456, 119 – 188 and 428 –
3
673 m /t, respectively. The large variation of WF results among the provinces is due to the factors
such as geographic and climatic variables in each province, cultivation calendar, and the variation

in yields.
For irrigation water requirement which is expressed by blue WF, the results show

that although both cassava and sugarcane in Thailand are mainly rainfed crops, rain water
contributes only about 80% and 71% of the total crop water requirement. The irrigation water

required to produce a ton of cassava, sugarcane, and molasses ranges between 47 - 160, 21 - 77,
3
and 79 – 278 m , respectively.

Green WF (Rain water) Blue WF (Irrigation water)
700

600
Cu.m. of water/ton feedstock 400
500

300

200

100
0
Min. Avg. Max. Min. Avg. Max. Min. Avg. Max.
Cassava Sugarcane Molasses
Figure 8.4 WF of major bioethanol feedstocks in Thailand

8.4.1.2 Comparative WF of bioethanol

The water footprint of bioethanol in Thailand varies between 1,396 – 3,105 L/L
ethanol as shown in Table 8.2. Based on the average WF values, cassava ethanol uses the

highest amount of water followed by molasses ethanol and sugarcane ethanol, respectively.
Nevertheless, there is the wide range in the results due to the variation in geographic and climatic

conditions and also the variation in yields of feedstocks. For example, the WF of cassava ethanol

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