Design and optimization of smart grid system based on renewable energy in Nyamuk Island, Karimunjawa district, Central Java

Abstract

Nyamuk Island in Karimunjawa District is one of the regions in Java that has no access to electricity grid. The electricity in Nyamuk Island relies on diesel engine which is managed by local government and only operated for 6 hours per day. It occurs as a consequence of high fuel cost. A study on smart micro grid system based on renewable energy was conducted in Combustion Engine and Propulsion System Laboratory of Institut Teknologi Bandung by using 1 kWp solar panels and a 3 kW bio based diesel engine. The fuels used to run the bio based diesel engine were diesel, virgin coconut oil and pure palm oil. The results show that the smart grid system run well at varying load and also with different fuel. Based on the experiments, average inverter efficiency was about 87%. This experiments proved that the use of biofuels had no effects to the overall system performance. Based on the results of prototype experiments, this paper will focus on design and optimization of smart micro grid system using HOMER software for Nyamuk Island. The design consists of (1) a diesel engine existing in Nyamuk Island whose fuel was diesel, (2) a lister engine whose fuel was from vegetable oil from Callophyllum inophyllum, (3) solar panels, (4) batteries and (5) converter. In this simulation, the existing diesel engine was set to operate 2 hours per day, while operating time of the lister engine has been varied with several scenarios. In scenario I, the lister engine was operated 5 hours per day, in scenario II the lister engine was operated 24 hours per day and in scenario III the lister engine was operated 8 hours per week in the weekend. In addition, a design using a modified diesel engine was conducted as well with an assumption that the modified cost was about 10% of new diesel engine cost. By modifying the diesel engine, the system will not need a lister engine. Assessments has been done to evaluate the designs, and the result shows that the optimal value obtains by the lister engine being operated for 24 hours a day in which the capacity of each component was 27 kWp PV, 7 kW lister engine, 26 kVA existing diesel engine, 40 kW converter and 128 batteries. The result is based on the lowest value of Net Present Cost (NPC) of $542.682 and Cost Of Electricity (COE) of $0.49.