**6. Discussion and Conclusions**

To respond rapidly to the increased electricity demand in countries with sustainable development, and to reduce environmental pollution, several countries have set national plans and policies for renewable energy production facilities [34]. Following this effort, the current study proposes the potential configuration of renewable energy production facilities for Chiang Mai University in Thailand to utilize local renewable resources. Two economic evaluations, COE and NPC, were used to assess the economic feasibility of the configuration. Related to research question 1, the potentially optimal configuration was organized by 12,780 kW-capacity PV array, 17,965 battery units, and 1525 kW-capacity electronic converter.

The configuration, which was composed of a PV array, a converter and batteries with a 5.38% annual real interest rate, achieved a \$0.728 per kWh COE with a 100% renewable fraction. The results of the simulation shows the possibility of an eco-friendly campus in Thailand by presenting the potential configuration of renewable energy generation systems for Chiang Mai University. Although the simulation results show heavy initial capital costs, the suggested systems can be practical in allowing the university to be a long-term eco-friendly campus. In addition, because the simulations did not consider the national grid system, which is used as the current electricity system of the university, the suggested systems can achieve greater performance by trading the electricity between the suggested systems and the grid connection. Moreover, using the suggested system shows the significantly reduced environmental pollutants. Related to research question 2, the emissions of greenhouse gas

are notably reduced. Moreover, compared to the current electricity system of Chiang Mai University, 179,510 kg of CO2, 778 kg of SO2, and 381 kg of NO and NO2 can be annually eliminated when the suggested system is installed and operated. It means that using the suggested system can provide environmental benefits for the university.

Compared to the findings of several previous studies conducted in Southeast Asia [12,14], the simulation results of the current study indicated that the suggested configuration can achieve 100% of renewable fraction with \$0.728 per kWh of COE. Considering the suggested configuration of previous studies in Thailand [14], the suggested configuration in the current study excluded the usage of diesel generators. Considering about \$0.858 per kWh of COE is provided by the national grid system in Thailand [35], the COE level presented by the suggested system, \$0.728 per kWh of COE, is considered as the economical configuration.

This study had several limitations. First, other policies on renewable energy in Thailand were not considered. For example, the Thailand governmen<sup>t</sup> started to apply feed-in-tariff policies to power production facilities [36,37]. Second, economic theories that can be used in the energy industry were not considered in the simulations. Prior studies found that there are notable economic theories validated in the renewable energy industry [38]. Third, the economic dynamics of developing countries were not considered. Several scholars indicated that the economic dynamics of developing countries can be a main hindrance to diffusing renewable energy facilities [39]. For example, the pay back period with the internal rate of return of the suggested system can be considered. Third, because the amount of electricity considered in Chiang Mai University is significantly heavy to simulate (17,654,195 kWh), the current study employs the 50% scaled electricity load information. Therefore, future studies should extend the findings of the current study by addressing these limitations.

**Author Contributions:** Conceptualization: E.P. and A.P.d.P.; Methodology: E.P. and S.J.K.; Data Collection and Simulation: E.P. and S.J.K.; Resources and Design: S.J.K.; Writing: E.P. and A.P.d.P.; Validation and Revision: E.P., S.J.K. and A.P.d.P.

**Funding:** This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-2018S1A5A8027730), and by the Dongguk University Research Fund of 2018. In addition, We acknowledge support from Universitat Jaume I (UJI-B2018-74).

**Conflicts of Interest:** The authors declare no conflict of interest.
