International Journal of Renewable Energy Development 11(1) 2022: 103-110 |103 IJRED-ISSN: 2252-4940.Copyright © 2022. The Authors. Published by CBIORE Contents list available at IJRED website Int. Journal of Renewable Energy Development (IJRED) Journal homepage: https://ijred.undip.ac.id Efficiency Improvement of Ground-Mounted Solar Power Generation in Agrivoltaic System by Cultivation of Bok Choy (Brassica rapa subsp. chinensis L.) Under the Panels Manoch Kumpanalaisatit, Worajit Setthapun, Hathaitip Sintuya, Surachai Narrat Jansri * Asian Development College for Community Economy and Technology (adiCET), Chiang Mai Rajabhat University, Mae Rim District, Chiang Mai Province, 50180, Thailand Abstract. An agrivoltaic system is a combination of solar power generation and crop production that has the potential to increase the value of land. The system was carried out at a 25-kW photovoltaic (PV) power plant located at the Asian Development College for Community Economy and Technology (adiCET), Chiang Mai Rajabhat University, Thailand. The growth and yield of bok choy ( Brassica rapa subsp. chinensis L.) and the solar power output were investigated and compared with the control. Moreover, the efficiency of the agrivoltaic system was evaluated. The results indicated that the average intensity of solar radiation of 569 W/m 2 was obtained. The highest power generation was recorded in the PV with crop production of 2.28 kW. Furthermore, the control plot of crop production at 35 days provided higher growth than bok choy plots under solar panels of 2.1 cm in plant height, 6 in leaf number, 2.2 cm in leaf length and 0.2 cm in leaf wide. High-yield of bok choy was also obtained in the control plot of 17.31 kg. Although the yield of bok choy is extremely low, possibly because of light intensity, crop cultivation under solar panels could reduce the module temperature to less than the PV control of 0.18 °C, resulting in increased voltage and power generation by around 0.09 %. Therefore, an agrivoltaic system is another option for increasing revenue and land equivalent ratio in solar power plants focusing only on electricity generation. However, suitable crops for the space under PV panels should be investigated further. Keywords: Agrivoltaic system, Ground-mounted solar power plants, Solar power generation, Solar power output, Bok choy. Article history: Received: 1 st Sept 2021; Revised: 7 th Oct 2021; Accepted: 12 th Oct 2021; Available online: 20 th Oct 2021 How to cite this article: Kumpanalaisatit, M., Setthapun, W., Sintuya, H., Jansri, S.N. (2022) Efficiency improvement of ground-mounted solar power generation in agrivoltaic system by cultivation of bok choy (Brassica rapa subsp. chinensis L.) under the panels. Int. J. Renew. En. Dev., 11(1), 103-110. https://doi.org/10.14710/ijred.2022.41116 1. Introduction Presently, solar energy can be converted into thermal or electrical energy. Solar energy is the cleanest and most abundant renewable energy source available at present, which can be converted into electricity directly by using photovoltaic (PV) systems (Missoum et al., 2021). Such systems usually consist of photovoltaic modules, batteries, charge controllers, inverters, load controllers, circuit breakers and wiring (Wasfi 2011). In 2018, the global capacity of photovoltaic power plants was over 500 GW (Jäger-Waldau 2018), most of which comprised ground- mounted photovoltaic power plants with a capacity of 471 GW. Moreover, the remainder is separated by 27.9 GW of solar roof tops (Europe 2018) and 1.1 GW of solar floating (Gamarra et al. 2019). The total land-use requirement for ground-mounted photovoltaic power plants was 1,448,612 Ha (Ong et al. 2013). In line with the global trend, ground-mounted photovoltaic power plants are still favored in Thailand. Solar power plant installations cover an area of * Corresponding author: surachai_nar@g.cmru.ac.th approximately 9,020 ha, which can presently generate total solar power at 2,819 MW per day (Chimres et al. 2016). By 2036, the Thai government plans to increase the number of solar farms to generate increased capacity at more than 6,000 MW (Department of Renewable Energy Development and Energy Efficiency 2015). The expansion of solar power generation will inevitably require more land area, which may affect not only the land use competition, but also food security in the future. While solar power plants have been promoted in Thailand and other countries, the areas under the solar panels have not been fully utilized because they focus only on solar power generation. Therefore, a combination of solar power generation and food production to increase the land benefit, also known as an agrivoltaic system, has been studied for its potential advantages (Valle et al. 2017; Dupraz et al. 2011). In addition, annual income could be increased by using agrivoltaic systems (Li et al. 2017; Mohammadi et al., 2017). Planting crops for agrivoltaic systems involves co-production between the solar power generation and crop production in a single space at the Research Article