Resiliency-Oriented Optimal Planning for a Grid-connected System with Renewable Resources and Battery Energy Storage

This article develops practical resiliency-oriented optimal planning models for a grid-connected system with renewable resources and battery energy storage. A long-term (ten-year) operation is conducted by incorporating grid outages, operating reserve, detailed models of electricity prices, and components' capacity degradations and costs. The number of grid outages per year as well as the days, starting time, and duration of the outages are adopted using probability distribution functions. Interest and escalation rates are updated in each year of operation to update the retail price, feed-in-tariff, and penalty rate of the electricity provider for the unsupplied power during grid outages. A novel operation strategy is developed for islanded and grid-connected modes of operation. The renewable-battery system is optimized for two cases: 1) a resilient system without load interruption; and 2) a resiliency-constrained system with partial load interruption. A case study in South Australia is conducted by incorporating the load profile of an educational campus and the actual weather data for a project lifetime of ten years. The resiliency-oriented optimal planning model is compared to the same system optimized by short-term data. It is found that the resiliency-constrained system achieves lower cost, battery capacity, and dumped energy with limited unsupplied energy compared to the resilient system, which has zero unsupplied energy. The proposed long-term resilient system is found to need 2.2-MWh battery capacity to efficiently supply 17.58-MWh electricity during the grid outages. The cost of electricity for the proposed resilient system is 23.77 ¢/kWh.