Pariyapat Nilsalab

Implications of the biofuels policy mandate in Thailand on water: the case of bioethanol.

The study assesses the implications of the bioethanol policy mandate in Thailand of producing 9 M litre ethanol per day by 2021 on water use and water deprivation. The results reveal that water footprint (WF) of bioethanol varies between 1396 and 3105 L water/L ethanol. Cassava ethanol has the highest WF followed by molasses and sugarcane ethanol, respectively. However, in terms of fresh water (especially irrigation water) consumption, molasses ethanol is highest with 699-1220 L/L ethanol. To satisfy the government plan of bioethanol production in 2021, around 1625 million m(3) of irrigation water/year will be additionally required, accounting for about 3% of the current active water storage of Thailand. Two important watersheds in the northeastern region of Thailand are found to be potentially facing serious water stress if water resources are not properly managed. Measures to reduce water footprint of bioethanol are recommended.

Water demand and stress from oil palm-based biodiesel production in Thailand

PurposeThe use and production of biofuels have been strongly promoted in Thailand. In order to achieve a 25xa0% renewable energy target in 2021, feedstock expansion is needed to satisfy the increased demand for biofuel production putting more pressure on freshwater resources. This is an important implication of biofuel production which has not yet been taken into consideration. Thus, this study intends to address the impact from freshwater use due to the biodiesel target based on life cycle assessment approach as well as to evaluate suitable areas for expansion of oil palm.MethodsThe amount of water for growing oil palm throughout its lifespan is estimated based on theoretical crop water requirement, while water demand for producing biodiesel is referred to from literature. Then, the potential impact on freshwater resources is assessed in terms of water deprivation using the water stress index of Thailand. The Alternative Energy Development Plan for 2012–2021 and areas recommended by the Ministry of Agriculture and Cooperatives are referred in this study. Additionally, two scenarios for increasing new plantation in suitable areas are proposed as expansion in a single region or spread over the three regions.Results and discussionThe highest water requirement for oil palm-based biodiesel production is found in the central region followed by the eastern and southern (4–9, 5–16, and 4–19xa0m3xa0L−1 biodiesel, respectively). This is because oil palm plantations in the central region are not yet fully mature. As a result, the ratio of crop water requirement associated to crop productivity will be reduced while the water productivity will be increased yearly in yield. Also, more than 99xa0% of the total water is required during the cultivation period. To achieve the 2021 biodiesel target with a concern towards the impact from freshwater use by means of low water deprivation, cultivating oil palm is recommended entirely in the eastern and the southern parts without expansion to the central region.ConclusionsThe impact on freshwater resources is an important implication of biofuel production as most of the water requirement of palm oil biodiesel was for oil palm cultivation. Accounting the water deprivation as one of the criteria on impact from freshwater use will provide useful support for selecting areas having less potential for inducing water stress in a watershed leads to people in these areas being less vulnerable to water stress.

Water stress index and its implication for agricultural land-use policy in Thailand

Abstract Land-use change and expansion for agriculture significantly affect freshwater resource availability which in turn results in different levels of water scarcity and competition among users in different areas and time. The study uses the water stress index as an indicator for determining the potential impact of water use considering water deprivation potential. Considering the case of Thailand, the temporal aspects of water withdrawal and availability have been analyzed and characterized as the monthly water stress index for the 25 watersheds in the country. Wide variations of monthly water stress index are obtained; extreme water stress is observed in the areas of the Chao Phraya and Tha Chin watersheds (the central region) during the dry season because of the large areas cultivating second rice (rice planted in dry season). The target of the Thai government on agricultural land-use change and zoning toward the conversion of about 0.37xa0M·ha of the upland paddy fields with low productivity to sugarcane was evaluated showing serious implications on the monthly water stress index of the relevant watersheds and the water scarcity footprint potentials of rice and sugarcane production. The results reveal that proper policy can help reduce the amount of water requirement for agriculture in June, July, August and September by about 60–220xa0M·m3, which in turn results in the decrease in monthly water stress index values. Nevertheless, appropriate measures of water resource management for agriculture still need to be designed to avoid water competition as well as protect the ecosystem.

Method Development for Including Environmental Water Requirement in the Water Stress Index

The overuse of human demand for water threatens the capacity of rivers or watersheds to retain their ecosystem services. Environmental water requirement (EWR) needs to be taken explicitly into account when assessing the impact from freshwater use on freshwater resources. Thus, we propose two perspectives for incorporating EWR into the Demand to availability (DTA) ratio of the water stress index (WSI); including it as a separate demand along with anthropogenic demands (Index 1) or reserving it from the available water (Index 2). It is expected that the more demand increases, the more pressure is put on the lowest priority sector. Index 2, by definition, gives the first priority to EWR whereas this is not so for Index 1. Thus Index 2 provides a more conservative approach in terms of the environmental protection and Index 1 allows a more flexible prioritization approach. Both these indices, however, allow flexibility of changing the EWR based on specific circumstances and context, thus making the evaluation more appropriate for water resource planning at both policy and implementation levels.