Analysis of Microgrid Electrification on Phaluai Island : A Minor Field Study in Thailand

Sammanfattning: Similar to numerous other nations, Thailand aims to achieve carbon neutrality by 2050 by reducing reliance on fossil fuels and increasing the amount of renewable energy sources in electricity generation. The objective of the Thai Provincial Electricity Authority (PEA) is to ensure electricity access for all Thai households and villages. The expansion of electricity production to small islands raises concerns about economic and environmental impact. Electricity accessibility on Thai islands is significantly limited due to difficulties of extending the electrical grid, as well as the comparatively higher costs associated with grid access in remote areas, in contrast to the mainland. One way to mitigate energy losses and emissions is by promoting decentralized electricity production and adopting renewable energy sources. Microgrids provide a solution that addresses these aspects, making them an attractive option to meet the growing demand of electricity sustainably in rural areas. This study examines the electricity situation in Thailand through a literature review of the current status of electricity and microgrid electrification. The case study then evaluates economic and environmental aspects of a microgrid project planned for Phaluai island, which has been chosen by the Ministry of Energy as a pilot project for the "Green Island" initiative, part of the "Reducing the Global Warming for King" campaign. The objective of the “Green Island” project is partly to promote clean energy on Phaluai. The study aims to optimize a microgrid design for Phaluai to compare with the proposed PEA project design, which includes a battery energy storage system, diesel generator, converter and solar power plant. However, the optimization also includes the potential use of wind turbine generators and biogas as additional fuel in the generator. To determine the optimal design, economical methods such as Net Present Cost (NPC) and Levelized Cost of Energy (LCOE), as well as environmental methods such as renewable fraction and CO2 emissions, are employed. These calculations are carried out using the HOMER Pro software. The results reveal that the optimal dimension for the microgrid includes 1,250 kW of solar PV, 300 kW generator, 500 kW converter and 1,925 kW of batteries, resulting in an NPC of 5.75 million USD and LCOE of 0.393 USD/kWh. Moreover, the microgrid demonstrates a renewable fraction of 89.6 % and CO2 emissions of 121,000 kg/year. Compared to the PEA proposed design, the obtained results have lower CO2 emissions and LCOE while higher NPC and renewable fraction. The optimized system also has more installed kW PV and battery than the PEA project plan. In the sensitivity analysis, the following variables are evaluated: electric load, diesel fuel price, discount rate, inflation rate, wind turbine price and biomass resources. All variables except wind turbine price affect the result in the form of changes in NPC, LCOE, CO2 emissions and renewable fraction. For some variable changes, e.g electric load, the optimal size of PV and batteries are also affected. In those cases, the optimal size for PV is instead 1,000 kW and for batteries, either 1,650 or 2,200 kW capacity.