The existing system was commissioned in 2004 as one of Thailand's first micro-grids. In 2012, upgrade was carried on several components and solar PV power was increased to 40 kW. The current arrangement schematic below represents the system as of May 2018 whereas the tentative upgrade arrangement schematic represents the optimized design to be implemented during the project throughout 2018-2019.
Current System Arrangement
The current system encompasses 40 kW of solar PV connected to a 60 kW Leonics Apollo inverter through MPPT charge controllers. An old and "rural" diesel generator system of roughly 50 kW is also connected to the inverter. A 240 kWh battery bank is connected to the inverter and is mainly charged using solar PV but diesel generators can also be used to charge the batteries.
The electricity is fed to the existing and well-maintained island electrical system. Old metering equipment is used to monitor individual consumption.
Houses mainly use electricity to power refrigerators, fans, lights, water pumps and electronics.
Tentative Upgrade System Arrangement
The upgraded micro-grid is currently on the design and optimization board. Expected new features include a state-of-the-art 50 kW diesel generator equipped with an auto-start to allow flexible and smooth power generation, a new Li-ion battery bank of 240 kWh and smart meters on houses and the medical center to facilitate billing and payment collection. Additional PV will be considered to optimize the renewable energy share of the whole system. Total solar power addition (if any) would be between 9 and 20 kW.
Existing Solar Infrastructure
The full 40 kW of solar PV will be used in the new upgraded system. The panels are well-maintained and can be re-used. Additional PV might be added depending on system optimization results. Existing solar infrastructures can be seen on the pictures below.