## 6 Conclusions  
According to the case study and simulation analysis in this research, the technoeconomic analysis of PV/BESS in BTM application can be performed through the HOMER Grid software to find the PV/BESS capacity configuration with the highest economic benefit, and the corresponding contract capacity scheme. This method proposed the applications to PV/BESS economic benefit analysis of different load profiles, TOU modes, etc. The comprehensive simulation analysis results of this research are as follows:  
According to the load conditions, the analysis includes electricity price data, PV/BESS equipment and O&M costs, limit conditions, and trends no PV/BESS installation as a benchmark for comparison. Through the HOMER Grid software, a combination scheme can be simulated and analyzed by resulting in the most economical solution with the capacity of a PV system of 8.25 MWp, BESS of 1.25 MW/3.195 MWh, and the corresponding contract capacity of 6 MW. The benefits for the economical solution are presented as 20-year project benefit of $3.591 \(\times\) 10\({}^{6}\), LOCE of $87.85 \(\times\) 10\({}^{-3}\)/kWh, IRR of 3.08%, ROI of 1.77%, discounted payback of 15.41 years, total electricity savings of 33.66%, RF of 29.6%, and excess electricity fraction of 2.93%. When the PV/BESS capacity is larger, the corresponding adjustable contract capacity is larger than the saved electricity charge. However, the investment cost of equipment and maintenance cost also increase, which reduces the project benefit. Based on sensitivity analysis to the highest project benefit  
Figure 16: Effect of varying real interest rates on the NPC and project benefit.  
Figure 17: Effect of varying real interest rates on the LCOE and discounted payback.  
scheme, the context of higher sunshine conditions and electricity prices leads to higher investment benefit, energy arbitrage benefit, ROI, IRR, and shorter discounted payback to reveal the benefits of installing PV/BESS.  
In the sensitivity analysis on cost, the capital cost ratio of the PV system is higher than that of BESS and PCS. In terms of the impact on economic benefits, the economic benefits obtained by reducing the capital cost of the PV system are significantly higher than reducing the capital costs of BESS and PCS. For the sensitivity analysis on the real interest rate, the increased real interest rate corresponds to decreased NPC, decreased project benefit, increased LOCE and longer discounted payback. Therefore, the context of low real interest rate is significant to the economic benefits of PV/BESS installation.  
Conceptualization, C.-Y.P. and C.-C.-K.; Formal analysis, C.-Y.P. and C.-T.T.; Funding acquisition, C.-C.K.; Investigation, C.-Y.P.; Methodology, C.-Y.P. and C.-T.T.; Project administration, C.-C.K.; Software, C.-T.T.; Validation, C.-Y.P. and C.-T.T.; Visualization, C.-T.T.; Writing--original draft, C.-Y.P. and C.-C.K.; Writing--review & editing, C.-C.K. All authors have read and agreed to the published version of the manuscript.  
The financial support for Energy Project provided by Taiwan Bureau of Energy is gratefully acknowledged according to Energy Storage System and Distributed Smart Microgrid Development Project for DC 750 V High Voltage.  
Not applicable.  
The authors declare no conflict of interest.