# Evaluation of the Coupling of a Hybrid Power Plant with a Water Generation System
## 4 Results
### Economic Analysis  
The total net capital investment of the proposed project including the hybrid solar/biomass and wastewater plants reaches the 211,526,743.00 \(\copyright\). Adjusting the calculations require the use of scaling exponents ranging from 0.8 to 0.9 depending on the component. The estimated costs are shown in Table 3. Required investment for other projects of the same magnitude, such as the Gemasolar power plant at the same location and with similar operational characteristics, are of a comparable scale [58]. The final investment calculated here is somewhat higher as a consequence of the hybridization of the plant and the implementation of the water reuse technologies [50]. The solar plant is responsible for an important part of the total investment of the power plant. This is mainly due to the heliostat field and the solar tracking system of the mirrors. To ensure good \begin{table}
\begin{tabular}{c c} \hline
**Component** & **Investment (\(\copyright\))** \\ \hline \multicolumn{3}{c}{**Solar Energy Capture System**} \\ \hline
**Mirrors** & 1,995,924.00 \\
**Metal Structure** & 13,971,469.00 \\
**Solar Tracker** & 9,702,409.00 \\
**Land Movement** & 1,746,434.00 \\
**Foundations** & 1,164,289.00 \\
**Assembly** & 3,326,540.00 \\
**Assembly Unit** & 831,635.00 \\ \hline \multicolumn{3}{c}{**Solar Energy Conversion System**} \\ \multicolumn{3}{c}{**Working Fluid (Molten Salts)**} & 82.00 \\
**Solar Tower Receiver** & 21,361,270.00 \\
**Mechanical System** & 2,967,182.00 \\
**Fire Protection** & 513,355.00 \\
**Inertisation System** & 285,197.00 \\
**Solar Tower Construction** & 3,497,735.00 \\ \hline \multicolumn{3}{c}{**Thermal Energy Storage System**} \\ \multicolumn{3}{c}{**Transfer System: Tanks \& Pipes**} \\ \multicolumn{3}{c}{**Initial Filling System**} \\ \multicolumn{3}{c}{**Construction**} & 671,164.00 \\ \hline \multicolumn{3}{c}{**Power Block**} \\ \hline
**Air Compressor** & 970,173.00 \\
**Biomass Combustor** & 1,196,008.00 \\
**Economizer** & 414,050.00 \\
**Evaporator** & 2,947,812.00 \\
**Supreheater** & 482,861.00 \\
**Reheater** & 1,021,964.00 \\
**Deaerator** & 14,728.00 \\ Condenser & 487,326.00 \\
**Pump 1** & 8,890.00 \\
**Pump 2** & 60,934.00 \\
**HSPT** & 1,365,160.00 \\
**IPST** & 5,237,489.00 \\
**LPST** & 1,102,629.00 \\
**FWH 1** & 650,061.00 \\
**FWH 2** & 26,197.00 \\ \hline \multicolumn{3}{c}{**Water Reuse Technologies**} \\ \hline
**Membrane Bioreactor** & 10,446,739.00 \\
**Ozonization** & 78,849.00 \\
**BAC \& GAC** & 1,810,718.00 \\
**Reverse Osmosis (RO)** & 1,931,911.00 \\
**Ultraviolet Radiation (UV)** & 112,469.00 \\
**Chlorination** & 20,731.00 \\ \hline \end{tabular}
\end{table} 
Table 3: Purchased equipment costs. tracing of the solar position and adequate rigidity of the components, a solar tracker and a metal structure are needed for each heliostat. Conditioning tasks to accommodate the plant, as well as required foundations for its proper assembly are also included in the cost calculations. Another subsystem with great impact on the final investment of the power plant is the system converting the solar radiation into thermal energy. The solar tower presents significant particularities when compared to other technologies. The solar receiver constitutes an essential element of the system and it must be placed at a considerable height from the ground. This leads to higher investment costs on both materials and construction, when compared to other solar technologies. Furthermore, the pumping of the molten salts to reach the height of the receiver requires powerful equipment within the salts mechanical system. Despite the great number of additional operational hours achieved with the thermal storage, its incorporation into the plant causes a significant increase in the investment cost. Thermal energy is stored within two insolated storage tanks with different temperatures. Vertical pumps are also required for each tank to drive the fluid towards the fixed receiver and steam generator.