Browsing by Subject "Wasserpolitik"

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An integrated computable general equilibrium model including multiple types and uses of water
(2015) Luckmann, Jonas Jens; Grethe, Harald
Water is a scarce resource in many regions of the world and competition for water is an increasing problem. To countervail this trend policies are needed regulating supply and demand for water. As water is used in many economic activities, water related management decisions usually have complex implications. Economic simulation models have been proven useful to ex-ante assess the consequences of policy changes. Specifically, Computable General Equilibrium (CGE) models are very suitable to analyze the consequences of water-related management decisions, as they consider the interlinkages between different sectors and economic agents within an economy. However, so far there is no CGE model which provides a holistic picture of the water sector including all aspects of provision, demand and management. Against this background, in this thesis a CGE model (STAGE_W) is developed which is especially focused on the water sector and provides a generic, integrated and flexible framework to incorporate various water sources from which several water activities produce water commodities of differing quality. These are consumed by other activities or by households. The applications presented in this thesis are to the best knowledge of the author the first CGE approaches to depict the recycling of wastewater and the provision of brackish groundwater as independent activities. Another novelty of the model is that it is capable to depict cascading water use. Furthermore, the inclusion of several water specific taxation instruments allows for a wide range of water policy simulations. To demonstrate the capabilities of the model, STAGE_W is applied to a Social Accounting Matrix for Israel. Based on this database several case studies are conducted which are presented in three scientific articles. Israel provides an ideal example as the country is strongly affected by water scarcity and is also among the world leaders regarding the development of new water sources and technologies. In the first article, a literature review on previously existing approaches of water depiction in CGE models is provided along with a detailed description of the specifics of STAGE_W. The model is applied to simulate a reduction of freshwater resources. The effects of this shock are analyzed with and without further increasing the desalination capacity. The results show that the economic effects are slightly negative under both scenarios. Counterintuitively, the provision of additional potable water through desalination does not substantively reduce the negative outcomes. This is mainly due to the high costs of desalination, which are currently subsidized in Israel. The second article simulates an abolishment of the discriminatory water pricing system currently established in Israel. Instead, two alternative schemes are introduced: price liberalization, which unifies the prices for all potable water consumers at cost recovery rates, and marginal pricing, lifting the potable water price to the cost of desalination. It is found that both schemes yield a double dividend by simultaneously saving water and increasing economic growth. Thereby, marginal pricing allows for larger water savings while price liberalization results in higher economic growth. In the third article, the model is further refined: the quantity of sewage available for reclamation is linked to the water consumption of economic entities connected to a sewer system. This allows to depict cascading water use and to endogenously estimate the marginal value of unpurified sewage. It is shown that a consideration of this link is crucial, if a high share of potable water is reclaimed and used. In this case, reducing the potable water consumption of municipalities also negatively affects the availability of reclaimed wastewater and thereby reduces its potential as a substitute for potable water. These case studies provide evidence of the validity of the model developed. The model results cannot necessarily be anticipated, as they are the outcome of complex interrelations within the model and none of the previous models has the capacity to capture all the relevant aspects of the water sector which influence these outcomes. Therefore, it is concluded that STAGE_W constitutes a helpful tool to implement a more sustainable management of water resources, allowing policy makers to ex-ante estimate the economy-wide effects of water related decisions. As the whole economy is depicted, a more holistic picture of effects resulting from changes in the water sector can be drawn in comparison to single sector models or cost-benefit analyzes.