Estimating Cost of Electricity of Resilient PV-based Grid-Tied Microgrids

Halted business from grid outages leads to financial damage suffered by the business. Photovoltaic and battery energy storage system paired microgrids are presenting an attractive opportunity for investors, by enabling them to generate and store their own energy and reducing their electricity cost for operations. A microgrid can, during grid outage, operate in islanded mode in which the loads at the microgrid remain energized by the BESS locally. In this paper models for the energy and financial transactions between microgrid and grid are formulated. A simulation is programmed from these models in which multiple grid reliability and microgrid configurations are simulated. The capability to island along with battery arbitrage, outages, and cost of electricity transactions are captured in a case study. It is shown that as grid reliability decreases, through increase in SAIFI, the optimal BESS size also increases. Finally, the lowest cost for electricity is found with small-storage + large-capacity PV systems because systems in this range show higher resilience against grid outages and benefit from lower component costs.