THE STUDY OF POTENTIAL AND EVALUATION OF ENERGY ECONOMICS OF SOLAR POWER SYSTEMS FOR COMMUNITY-LEVEL AQUACULTURE

Abstract

The objectives of this study were to investigate the operational potential and evaluate the energy economics of using a solar photovoltaic (PV) system for aquaculture at the community level, specifically within the Tha Thon Kwao Community Enterprise Group for Agricultural, Vegetable, and Herbal Cultivation in Saraphi District, Chiang Mai Province. The design findings indicated that the optimal solar PV system size was 900 Wp, utilizing a single 450 W monocrystalline solar panel to power a 350 W DC motor paddlewheel aerator for approximately 9 hours per day. Additionally, another 450 W panel was used to charge two 12 V 100 Ah batteries to supply backup power to the aerator during nighttime hours (from 11:00 PM to 4:00 AM), a period when dissolved oxygen (DO) levels in the water become normally lower. An environmental monitoring system was used to continuously track DO levels, which ranged from a minimum of 1.30 mg/L to a maximum of 7.50 mg/L, with an average of 3.70 mg/L which is sufficient to sustain fish life. The annual energy assessment showed that the solar PV system could generate approximately 1,383.35 kWh/year, reducing conventional electricity usage for aeration by 90.24% compared to operating the aerator for 12 hours per night. The economic evaluation revealed electricity cost savings of 6,225.08 Baht/year, a payback period of 6.35 years, a net present value (NPV) of 15,898.71 Baht, and an internal rate of return (IRR) of 10.53%. As a result of the system's implementation, the community enterprise was able to shorten the fish farming cycle from 7 months under natural method condition to only 4 months.