A framework for joint management of regional water-energy ... - Orbit

Figure 2. Mean annual irrigation requirements (source: Wriedt et al., 2009).
energy units, using an aggregation methodology briefly described in Section
4.1 and detailed in Pereira-Cardenal et al. I.
In the optimization methods used to couple the water and energy systems,
irrigation allocation was considered as a constraint that must be satisfied (Pereira-Cardenal
et al. I), or as a decision variable that is adjusted to achieve
maximum benefits (Pereira Cardenal et al. II, III). In the second case, an irrigation
demand function must be used in order to determine optimal water
allocation.
Two demand functions were used based on the spatial scale of the problem
and data availability. In Pereira-Cardenal et al. II, which considers irrigation
aggregated at the peninsula level, net benefits and allocation distribution
among crops in Spain (MMA, 2007) were used to construct the demand function
shown in Table 2. In Pereira-Cardenal et al. III, which considers irrigation
aggregated at the river basin level, data on annual water allocations for
ranges of net benefits in each river basin in Spain (MMA, 2007) were used to
define irrigation users as follows (Table 3). A constant willingness to pay for
water was assumed for all water allocations, and the net benefits were used as
a proxy for marginal benefits. The annual values were also distributed in proportion
to monthly observations in the Ebro Basin, and converted to energy
units.
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