Environmental Water Footprints by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9789811325083
Publisher: Springer Singapore

3.5 Extensions to Optimization Models, Water Restrictions, LCA-EIO Models, Etc

When we want to address the effects in an economy of greater or lesser availability of water, or the restrictions that suppose for example maximum levels of water pollution, we can make use of the presented framework (we do not make use here of for the expansion for n regions) and extend it to solve an optimization problem with restrictions such as those posed in the dual problems that follow:

(5)

If is the vector of added value per unit of output and the vector of water uses per unit of output, the first problem requires the maximization of the income or value added of the economy under the condition that a certain final and previously established demand is covered, and that the uses of water do not exceed a provision b. The second problem is equivalent to the first, but expressed in dual variables or shadow prices; gives the shadow prices of obtaining the fixed levels of demand (the variation in the optimum value added when the demand requirement increases by one unit) and the effect on the optimal added value of the increase of one unit in the initial allocation of water. Undoubtedly the problems to be addressed may be more complex, but their formulation will be essentially similar (see, for example, Sánchez-Chóliz and Duarte 2005, López-Morales and Duchin 2014). These type of applications try to minimize the use of water, but typically also of other factors of production, looking for the global costs minimization (see Duchin 2005; Cazcarro et al. 2016b). In the final discussion we will refere back to these models to comment on future and open lines of research which can improve the interest of water footprint studies for policy, scenarios, etc.

We have also referred to process analysis type of studies, LCA, LCI (Life Cycle Inventory), etc. as examples of bottom-up approaches, and to input-output models as an example of top-down, and it may seem that they are completely different frameworks. On the contrary, following intitial attempts of adding input-output results which were based on disaggregation of monetary input-output tables or also process based models (Bullard and Pilati 1976), a highly relevant literature has rigourously addressed their similarities (Suh 2004a, b; Suh et al. 2004; Suh and Kagawa 2005; Suh and Heijungs 2007; Ferrão and Nhambiu 2009), and formulated the hybrid LCI-IO framework or also so called Hybrid EIO-LCA (process-based LCA and economic input-output analysis-based LCA). The Waste Input-Output model (Kondo and Nakamura 2003; Nakamura 1999; Nakamura and Kondo 2002, also a generalization of the Leontief–Duchin environmental input–output (EIO) model Duchin 1990; Leontief 1970) can be also seen as a general framework for hybrid LCA involving waste management and recycling, and hence it can be of particular interest for modelling waste water treatment.

In LCA, a usual algebraic formulation is to consider an external demand of process output be given as . The use of tilde indicates any activity in the foreground system. When the technical coefficients of the

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.