# Techno-Economic Analysis of Waste Heat Recovery in Automotive Manufacturing Plants
## 4 Results and Discussion
### Economic Analysis of Different Scenarios
Each case has a different investment cost between 0.87 and 2.57 million EUR, indicated in year 0 as initial installation expenses. Starting in year 1, the system is expected to be able to generate electricity and contribute revenue. The revenue rates of each case depend on the capacity of electricity generation. Therefore, Figure 7 shows that Case 4 has the quickest positive cumulative discounted cash flow due to the lowest investment and SIC. Figure 6: Distribution of investment costs across different system configurations: (**a**) Case 1—system with PV panels and a recuperator, (**b**) Case 2—system without PV panels, but with a recuperator, (**c**) Case 3—system with PV panels and no recuperator, and (**d**) Case 4—system without PV panels and without a recuperator. Furthermore, the economic assessments for each case, including key metrics such as estimated power output, annual energy production, investment cost, SIC, NPV, PBP, LCOE, and ROI, are presented in Table 6. In terms of output power, Cases 1 and 3 generate approximately 1.31 MW each, as both incorporate PV systems. By contrast, Cases 2 and 4, which exclude the PV component, produce a lower power output of around 0.47 MW. This difference highlights the contribution of PV integration to enhanced power generation. Regarding annual energy production, Cases 1 and 3 achieve a higher energy output of approximately 4.30 GWh, significantly more than Cases 2 and 4, which produce around 2.95 GWh. This increase is attributed to the additional energy supplied by the PV system in Cases 1 and 3. Incorporating a PV system and recuperator in the ORC system, as seen in Case 1, results in high investment costs, reaching up to 2.57 million EUR. In contrast, Case 4, excluding both the PV system and the recuperator, offers a low investment cost of approximately 0.87 million EUR. However, investment cost alone is insufficient for a comprehensive economic evaluation; thus, SIC is used to provide a more balanced assessment, as it accounts for both investment cost and power production. The SIC results show that Case 4 achieves low SIC, around 1.83 thousand EUR/kW, reflecting its cost efficiency despite the lower power output. In contrast, Case 2, without a PV system, but including a recuperator, has a high SIC, at approximately 2.08 thousand EUR/kW. Although Case 1 has the highest upfront investment, its SIC remains relatively competitive and is notably lower than that of Case 2. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Parameters** & **Unit** & **Case 1** & **Case 2** & **Case 3** & **Case 4** \\ \hline Recuperator & - & Yes & Yes & No & No \\ PV system & - & Yes & No & Yes & No \\ Estimated power production & kW & 1310.31 & 476.97 & 1310.31 & 476.97 \\ Estimated annual total energy & MWh & 4307.29 & 2953.29 & 4307.29 & 2953.29 \\ production & EUR & 2,568,404.57 & 993,590.97 & 2,448,520.97 & 873,707.37 \\ SIC & EUR/kW & 1960.15 & 2083.10 & 1868.66 & 1831.76 \\ NPV & EUR & 654,541.23 & 1,216,220.71 & 774,425.83 & 1,336,103.31 \\ PBP & years & 14.06 & 7.13 & 13.31 & 6.20 \\ LCOE & EUR/kWh & 0.064 & 0.041 & 0.061 & 0.037 \\ ROI & \% & 25.48 & 122.41 & 31.63 & 152.92 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary of the economic assessment. Figure 7: Cumulative discounted cash flow for each case. In terms of NPV and PBP, Case 4 presents a high NPV of approximately 1.33 million EUR, while Case 2 has a slightly low NPV of around 1.21 million EUR. Interestingly, cases that incorporate a PV system, such as Case 1 and Case 3, tend to have low NPVs, with values of about 0.65 million EUR and 0.77 million EUR, respectively. This suggests that, despite increasing power production, the PV system reduces profitability when measured by NPV. The impact of PV on economic performance is further evident in the PBP results. Cases with PV systems, such as Case 1 and Case 3, have longer PBPs, extending beyond thirteen years, making them slower to recover their investment costs.