A Comparative Study of Battery Energy Storage Systems in Isolated Grids: Novel Approach to Shave Peaks & Optimize Energy Costs

Isolated power systems are typically found in rural areas that are far separated from the power grid. Rapid decrease in BESS (Battery Energy Storage Systems) cost provides new opportunities and preferences for utilities to store cheap energy at low loads and power out that energy at peak loads. BESS is installed to shave or level demand during peak hours in an isolated system can avoid the use of peaking generations mostly coming from oil fuels. Considering the BESS function for peak shaving, the approach is to simulate the unit commitment of different battery sizes at 10 MW, because the use of oil fuels about 10 MW at peak load, so the simulation will be representing the total energy of the battery needed by the system. Based on the simulation, the life cycle cost is significantly greater than the benefit at all power and energy ratings. The purpose of this paper is to demonstrate the comprehensive technical and financial analysis needs to find the optimum battery type and capacity to provide optimum impact and financially benefit the system with an approach to shaving peaks and energy costs. A study-case method is demonstrated by taking an isolated system as the base and BESS performance can accelerate voltage in the subsystem for every substation when discharging at peak load. The simulation results that 10 MW/10 MWh lithium-ion batteries provide the highest benefit compared to the life cycle cost.