# Economic Analysis of a Zero-Water Solar Power Plant for Energy Security
## 3 Results and Discussion
### Economic Analysis of the Overall CSP Plant  
The fixed capital investment (FCI) of the 20-MW solar power plant, with thermal storage and using the Earth-CATs, is summarized in Table 4[41,46]. The plant is able to produce 80 GWh/year and has a capacity factor of 55% [33]. Direct costs include the equipment costs and consist of the solar field and the heat transfer fluid (HTF) system, the thermal storage system, the power block, and the cooling system. The solar field includes the mirrors together with the tower and the receiver. For the thermal storage, a two-tank system using molten salt that can produce 700 MWh\({}_{\text{th}}\) per day is considered, i.e., it can ensure 14 h of operation at maximum capacity. The power block is a conventional steam turbine connected to the grid. Direct costs are completed with the labor costs. Costs such as the project development and management are included in the indirect costs. The total costs of the plant, including the Earth-CAT system amount to EUR 13,728/kW. The reported total installation costs of CSP plants with storage capacities of 8 h or more were in the range of EUR 3343/kW to EUR 4817/kW during 2018 and 2019 [47], costs significantly lower than that calculated in this study. In addition to the FCI, the land and O&M costs are estimated. The total surface of 195 hectares of the plant is considered to integrate the Earth-CAT system taking advantage of the buried pipes. The land cost is considered here equal to EUR 5/m\({}^{2}\). The annual fixed O&M costs of the plant are calculated using a specific cost of EUR 53.3/kW, while the variable O&M costs are estimated as 10% of the total O&M costs. [48]. Lastly, it is assumed that 30 labor positions are required for the O&M of the plant [35]. Based on the inputs described, and the assumptions presented in Table 2, the annual levelized TRR is estimated. The total capital investment (TCI) is obtained after adding the land costs and other outlays such as startup costs, working capital, or allowances for funds during construction. The annual capital recovery schedule is then escalated together with the rest of expenses presented in Equation (3). The overall results of the economic analysis of the plant with the Earth-CATs with a conventional air-based system and with a conventional water-based system are summarized in Table 5. The plant with a conventional air-based system is considered to have 6.8% less annual power generation, compared to the 80 GWh/year (i.e., 74.56 GWh/year) [46]. For the water-based system, water costs of EUR 1/m\({}^{3}\) are included in the annual O&M costs [2]. The investment costs of both conventional cooling systems are considered to be part of the presented costs of the power block. During the last decade (2010-2019), the average LCOE of CSP plants decreased from EUR 283.72/MWh to EUR 149.24/MWh [49]. Specifically, for a 20-MW solar power plant using dry cooling, a TCI of MEUR 174.66 and a LCOE of EUR 138.33/MWh were obtained [46]. When wet cooling was used in the same plant, the two parameters were equal to MEUR 171.38 and EUR 126.69/MWh, respectively. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Costs** & **Unit Cost** & **Units** & **Total (EUR)** & **(\%) of Associated** \\ \hline Initial investment & & & 148,285,791 & \\ Material and equipment & & & 102,707,181 & 69.26 \\ PVC pipes (material) & 30.76 EUR/m & 300 m/pipe \(\times\) 10,965 pipes & 101,185,020 & 98.52 \\ Fans & 319 EUR/unit & 2193 units & 699,567 & 0.68 \\ Particle filters & 156 EUR/unit & 2193 units & 342,108 & 0.33 \\ Dehydrated filters & 156 EUR/unit & 2193 units & 342,108 & 0.33 \\ Valves, electronic and electrical & & 10\% extra cost of the equipment cost & 138,378 & 0.13 \\ installations & & & 45,578,610 & 30.74 \\ Labor & & & 24,861,060 & 54.55 \\ Excavation & 2.0 EUR/m\({}^{3}\) & 10,358,775 m\({}^{3}\) & 20,717,550 & 45.45 \\  & & & 67,106 & \\ Cleanings, overhauls and repairs & & & 65,790 & 98.04 \\ Others & & 2\% extra cost of the annual O&M cost & 1316 & 1.96 \\ \hline \hline \end{tabular}
\end{table}