*2.5. Future Costs*

The capital cost of a desalination technology *Ccap*(*t*) at year *t* is given by Equation (12). The capital cost decreases with the cumulative installed capacity *X*(*t*) given by Equation (13). In these equations, *a* is a normalization constant, *b* is an empirical parameter based on learning rates, *K* is the saturation capacity, *r* is the growth rate, and *tm* is the year when half of the saturation capacity is installed [26]. The parameter values for each desalination technology are given in Table 5, while the future cost parameters for energy components are shown in Appendix D.

*Ccap*(*t*) *Ccap*(2015) <sup>=</sup> *<sup>a</sup>*[*X*(*t*)]−*<sup>b</sup>* , (12)

$$X(t) = \frac{K}{1 + \exp[-r(t - t\_m)]},\tag{13}$$


**Table 5.** Future cost parameters of desalination technologies.
