## 2 Materials and Methods
### Case Studies Design
#### 2.3.2 Case Studies Parameters and Assumptions  
The main parameters and assumptions for the case studies are presented below:  
* The system is considered to be installed on Naxos island in the Aegean Sea, Greece. * Typical Meteorological year data are utilized for the Cyclades complex islands in the Aegean Sea, Greece. * The prices of all system components are on par with commercial pricing in Greece. * The interest rate is assumed at 5% and the investment period is equal to 20 years. * The lifetime of all components is considered to be 20 years and 1 battery exchange is considered in this 20-year period, on par with the current 10-year warranties of high-quality lithium batteries. * High efficiency (~20% efficiency) PV modules are considered. * Ener E200 18.5 kW wind turbines are considered in order to be able to do optimizations for the 100 m\({}^{3}\)/day system and Hummer 200 kW wind turbines for the 600 m\({}^{3}\)/day \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Case Study No.**} & **Water Consumption (m\({}^{3}\)/Day)** & \begin{tabular}{c} **Nominal Water** \\ **Production of** \\ **Desalination** \\ **Plant (m\({}^{3}\)/Day)** \\ \end{tabular} & \
\begin{tabular}{c} **Renewable** \\ **Energy** \\ **Technologies** \\ \end{tabular} &
\begin{tabular}{c} **Type of** \\ **Interconnection** \\ \end{tabular} & **Water Tank (Days)** \\ \hline
8 & 100 & 100 & PV & Autonomous & 3 \\ \hline
9 & 100 & 100 & Wind & Autonomous & 3 \\ \hline
10 & 100 & 100 &
\begin{tabular}{c} Hybrid (PV and \\ Wind) \\ \end{tabular} & Autonomous & 3 \\ \hline
11 & 100 & 100 & PV & Autonomous & 10 \\ \hline
12 & 100 & 100 & Wind & Autonomous & 10 \\ \hline
13 & 100 & 100 &
\begin{tabular}{c} Hybrid (PV and \\ Wind) \\ \end{tabular} & Autonomous & 10 \\ \hline
14 & 100 & Optimal & Optimal & Autonomous & Optimal \\ \hline
15 & 100 & 100 & Geothermal & Autonomous & 1 \\ \hline
16 & 600 & 600 & No renewables & Grid-connected & 1 \\ \hline
17 & 600 & 600 & PV &
\begin{tabular}{c} Grid- \\ connected/Net- \\ metering \\ \end{tabular} & 1 \\ \hline
18 & 600 & 600 & PV & Autonomous & 1 \\ \hline
19 & 600 & 600 & Wind & Autonomous & 1 \\ \hline
20 & 600 & 600 &
\begin{tabular}{c} Hybrid (PV and \\ Wind) \\ \end{tabular} & Autonomous & 1 \\ \hline
21 & 600 & 600 & PV & Autonomous & 3 \\ \hline
22 & 600 & 600 & Wind & Autonomous & 3 \\ \hline
23 & 600 & 600 &
\begin{tabular}{c} Hybrid (PV and \\ Wind) \\ \end{tabular} & Autonomous & 3 \\ \hline
24 & 600 & Optimal &
\begin{tabular}{c} Optimal \\ Autonomous \\ System \\ \end{tabular} & Autonomous & Optimal \\ \hline
25 & 2000 & 2000 & No renewables & Grid-connected & 1 \\ \hline  & 2000 & 2000 & PV &
\begin{tabular}{c} Grid- \\ connected/Net- \\ metering \\ \end{tabular} & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Cont. one. In reality, a single higher rated power wind turbine would be chosen in any project in order to minimize costs rather than deploying a small wind farm. * Supporting works for the desalination system are not considered, since their cost is dependent on the specific site realities. * Brine treatment and disposal costs are not considered. * High quality lithium-ion batteries with 10 years of manufacturers guarantee are considered. There is an increasing trend of commercial lithium-ion batteries to come in modular racks which can be expanded based on the needs of the consumer with an ease facilitating system integration. This also facilitates the optimization process. Such a battery is considered with a base size of each module equal to 2560 Wh. * The water consumption profile is considered constant on an hourly basis throughout the day. * Operation and maintenance costs (OPEX) as a percentage of produced water or installed power used are based on bibliography [45; 46]. * The minimum battery size considered in optimizations is able to meet at least 1 h of the load for the largest system considered.