## 4 Economic Analysis
### Cost Comparison (Economic Analysis)  
By comparing the system cost according to the presence or absence of a base power source in Figure 6, it was estimated that the cost of a system with a base power source would be USD 533,849.15, cheaper than that of a system without a base power source, resulting in a cost reduction of about 30.03%. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Component** & **Unit Price** & **Installation Capacity** & **Cost (USD)** \\ \hline PV (\(PV_{E}\)) & 1083 \$/kW & 442.15 kW & 478,846.93 \\ \hline ESS (\(ESS_{0}\)) & 450 \$/kWh & 1375.96 kWh & 619,182.77 \\ \hline Fuel cell (\(F_{0}\)) & 4167 \$/kW & 35.00 kW & 145,845.00 \\ \hline \multicolumn{3}{c}{Total} & 1,243,874.70 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Cost of the system designed with a base generation power source. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Power Generation** & **Referenced Research** & **Current Research** \\  & **(Without Base Load** & **(With Base Load** \\  & **Power Generation)** & **Power Generation)** \\ \hline PV (\(PV_{E}\)) & 715.84 kW & 442.15 kW \\ \hline ESS (\(ESS_{0}\)) & 2227.70 kWh & 1375.96 kWh \\ \hline Fuel cell (\(F_{0}\)) & - & 35.00 kW \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of the system design according to the presence or absence of a base power source. \begin{table}
\begin{tabular}{c c} \hline \hline
**Component** & **Unit Cost** \\ \hline PV generation system & 1083 \$/kW \\ \hline ESS & 450 \$/kWh \\ \hline Fuel cell generation system & 4167 \$/kW \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Unit cost by system components. Even though the fuel cell, which is a rather expensive power source, was used as the base power source in this study, improved economic feasibility was obtained compared to the referenced design method. However, the design method proposed in this study cannot always secure superior economic efficiency over the referenced design method. There will be fluctuations in the results of the economic analysis based on differences in the types of base power sources and the unit cost. In other words, if the unit price of the base power source is too high, then a design method that does not take the base power source may be more favorable in terms of economics. Therefore, we propose criteria for deciding whether to adopt a base power source in the system design according to the unit cost. Equations (9) and (10) reorganize the capacity of the ESS as the capacity of the PV power generation system. To analyze the relationships between the system components, the rest of the variables except for the variables related to the power generation source in (9) are treated as constants. Other variables, except those related to the power generation source, such as \(ESS_{0}\) and \(PV_{E}\), are also treated as constants using the figures presented in Section 2, thus forming (12). \[ \begin{split} ESS_{0}=\left\{\frac{3.56}{0.965\times 0.9\times 0.9}-0.47 \times 3.56\times 0.965\times(1-0.01)\right\}PV_{E}\left[kWh\right]\\ ESS_{0}=2.96 PV_{E}\left[kWh\right]\end{split}  \tag{12}\]  
From (12), we can see that the capacity of the ESS is presented as 2.96 times the PV power generation capacity regardless of the magnitude of the power load. In addition, this ratio is the same regardless of whether the base power source is adopted. We will derive the criteria for deciding whether to adopt the base power source into the system design based on the unit cost of the base power source. If the total system capacity is 1, then the base load (A) and remaining load (B), excluding the base load, can be expressed as (13), in which the base load (A) and remaining load (B) are ratio values rather than actual capacity values. \[\text{A}+\text{B}=1 \tag{13}\]  
The system unit cost of the base power source (fuel cell) is expressed as \(x\), the PV power system unit price is expressed as y, and the ESS unit price is expressed as z.