Eco-Friendly Education Facilities: The Case of a Public Education Building in South Korea

Since the importance and effects of national energy policies, plans, and roadmaps were presented in South Korea, the role of renewable energy resources has received great attention. Moreover, as there is significant reasoning for reducing and minimizing nuclear and fossil fuel usage in South Korean national energy plans, several academic scholars and implementers have expended significant effort to present the potential and feasibility of renewable energy resources in South Korea. This study contributes to these efforts by presenting potential sustainable configurations of renewable energy production facilities for a public building in South Korea. Based on economic, environmental, and technical information as well as the presented simulation results, it proposes an environmentally friendly renewable energy production facility configuration that consists of photovoltaic arrays, battery units, and a converter. Subsidies for installing and renovating such facilities are also considered. The potential configuration indicates $0.464 as the cost of energy, 100% of which is renewable. Potential limitations and future research areas are suggested based on the results of these simulations.


Introduction
After the peaceful turnover of political power in 2017, the new South Korean government is attempting to reform national energy policies and plans.During this reform process, the government is aiming to phase out the usage of nuclear energy.One of the major decisions undertaken in this regard was the suspension of the construction of the fifth and sixth nuclear reactors in Kori when the construction process was 28.8% complete [1].Although construction resumed when the government was implored to do so by a jury of 471 randomly selected citizens, the government decided that no new nuclear power plants in South Korea should be constructed [2].
Therefore, exploring, adopting, and using new energy resources is one of the most important research areas for establishing national energy policies and plans.As nuclear energy constitutes approximately 12% of South Korea's national energy supply system, alternative energy resources could be unpalatable or infeasible [3].Moreover, because of the Paris Agreement, which requires South Korea to reduce its large greenhouse gas emissions, increasing the use of fossil fuels would also be infeasible [4].
Accordingly, the South Korean government is aiming to implement renewable energy resources.Approximately 4.6% of primary energy in South Korea was provided by renewable energy production facilities in 2015, with an annual growth rate of 15.2% [3].Moreover, South Korea's energy dependence on foreign countries is very high, and compared with other countries, oil price fluctuations have a greater effect on the South Korean economy [5].Thus, ensuring reliable energy production and securing stable energy resources are important.
The South Korean government has pursued the expansion and distribution of renewable energy production facilities to achieve its goal that, by 2035, 11% of primary energy in South Korea should be generated from renewable energy resources.To achieve this goal, the government established The fourth basic plans for the technology development, usage, and distribution of new and renewable energy, with detailed programs for promoting each energy source [6].Based on these promotion programs, the duty ratio of the renewable portfolio standards was revised and enhanced.All public buildings with a certain total floor area that are planned to be constructed, reconstructed, or enlarged should have at least 21% of their energy supplied by renewable resources [7].Therefore, both central and local South Korean governments urge public organizations and institutions to include electricity and energy production facilities that use renewable resources.For this reason, several studies have attempted to investigate the feasibility of implementing renewable energy production facilities in diverse public buildings, including a public university, local government office, and multi-purpose public buildings [8].
Considering this background, this paper presents a case study for the economic and environmental feasibility of renewable energy production systems in a public education building in South Korea.
After careful simulation, a potential configuration of a renewable energy production system for the building is suggested.

Review of Prior Feasibility Studies in South Korea
Several studies have attempted to investigate the feasibility of renewable-oriented power generation facilities in South Korea.Table 1 summarizes the key prior studies.As presented in Table 1, the majority of prior studies have focused on specific regions such as certain islands or areas.This means that only a few studies have explored the sustainable cases of renewable energy facilities for public buildings in South Korea.

Location and Facilities
This study focused on an elementary school located in southeastern South Korea.To investigate the economic and environmental feasibility of potential renewable energy production facility configurations for school buildings, this study selected Samrangjin Elementary School in Miryang (SESM), which has smart meter facilities to record the school's hourly electricity usage.The location of this school is 35 • 23 44.76 N and 128 • 50 15.89E, and it has approximately 100 students and 40 members of staff.The school has four buildings: the main education building, education support building, warehouse, and kindergarten building.Figure 1 presents the location and an overview of SESM in South Korea.

Energy Load Information
SESM's energy system mainly uses electricity provided by the national grid.In 2016, SESM used 99,263 kWh.The SESM electricity load shows a scaled annual average electricity level of 223 kWh/d with a load factor of 0.464.

Renewable Energy Resources
This study uses the solar resource data provided by the National Aeronautics and Space Administration (NASA).Table 2 summarizes the monthly baseline data.Annual average solar daily radiation is 4.259 kWh/m 2 /d, with a solar clearness index of 0.514.The wind resource information of SESM is collected and provided by the Korea Meteorological Administration.Figure 2 summarizes the monthly wind speed.

Annual Real Interest Rate
To present precise simulation results, the actual South Korean interest rate is computed and used in the simulations [18,19].Based on a report by the Bank of Korea, an annual interest rate of 3.51% is used.

Evaluation Criteria
To explore the results of the simulation, the suggested sustainable configurations are ordered by two economic outputs: the cost of energy (COE) and net present cost (NPC).The COE is defined as the mean cost of generating 1 kWh electricity by the suggested configuration, while the NPC is defined as the total cost of installing, utilizing, replacing, and performing the functions of the suggested configuration throughout the project [15].In addition, the project lifespan used by this study is 25 years.

Renewable Electricity Production Systems
To introduce the configurations of the sustainable renewable energy production system, the economic information of each component that can be used in the configurations should be investigated.Based on detailed economic information about the components from previous studies, Table 3 summarizes the specific economic information about the components employed in the simulations presented here.In addition, the standard electricity price, which is introduced by KEPCO, is used in the grid connection.

Results
The sustainable configuration, which contains PV panels, battery units, and a converter, is proposed based on the simulation results (Table 4).Table 5 summarizes the total and annual costs of the proposed configuration.The suggested configuration for providing reliable and sustainable energy services to SESM includes 500 kW-capacity PV arrays, a 247 kW-capacity converter, and 202 battery units (Table 4).

Cost Category Component ($) Capital ($) Replacement ($) O&M ($) Salvage ($) Total ($)
Total NPC ($) PV array the electricity produced by the suggested system fulfils the electricity demand of SEMS (AC primary load), while 86% is sold through the grid connection.Altering the current grid connection to the suggested configuration is expected to reduce annual emissions of carbon dioxide, sulfur dioxide, and nitrogen oxide by 308,661 kg, 1338 kg, and 654 kg, respectively.

Discussion and Conclusions
To develop more sustainable and eco-friendly energy plans in South Korea, the government intends to distribute renewable energy generation facilities to public buildings and organizations.Considering this trend, this study introduces a potential sustainable renewable energy generation facility configuration to fulfil the electricity demand of SEMS using local, natural resources.To evaluate the suggested configurations of the simulations, both the COE and the NPC are computed and employed.
The suggested configuration achieves 100% renewable energy, with a COE of $0.464.Although the COE of this configuration is higher than the current price of the South Korean grid connection [20], the suggested configuration can be applied to SEMS, a public education building in South Korea, as an on-site test.In addition, the simulation results also indicate that subsidies are an important issue in distributing and maintaining renewable energy production facilities [21].
As using renewable energy production facilities significantly reduces greenhouse gas emissions, the South Korean government and associated industries should distribute renewable energy production facilities [22].According to the Paris Agreement, which introduces a mandatory level of greenhouse gas emissions for 195 nations, the South Korean government should also attempt to distribute more sustainable energy production facilities within its electricity system [23].
Although both economic and environmental information, which can be applied to the potential configuration of SEMS, was investigated considering subsidies for renewable energy production facilities in South Korea, this study has several limitations.First, the economic aspects of the certified reduction in greenhouse gas emissions were not considered.This can produce better economic results on utilizing renewable energy resources than the simulation results [24].Second, economic theories in the renewable energy industry were not considered in the simulations.Several studies have already indicated that various economic theories can be applied and used in the renewable energy industry and market [25,26].Therefore, future research should aim to eliminate the limitations of the current study.

Figure 1 .
Figure 1.The location of SESM in South Korea.

Table 1 .
Summary of prior feasibility studies of renewable energy facilities conducted in South Korea (W: Wind turbines, P: photovoltaic (PV) arrays, D: Diesel generators, B: Battery units, C: Converters, K: Kerosene generators).

Table 2 .
Monthly solar resource information for SESM.

Table 3 .
Economic information about the components (* The supporting policies and plans by the South Korean government are applied).

Table 4 .
Summary of the suggested configuration from the simulation results for SEMS.

Table 5 .
Costs of the suggested energy system configuration for SEMS.

Table 6 .
Annual electricity consumption and production of the suggested configuration.