Optimal Battery Sizing for Storm-Resilient Photovoltaic Power Island Systems

Photovoltaic systems with battery storage are analyzed from the perspective that they can operate as a local power island in circumstances of storm-damage or other grid outage. The specific focus is to determine the optimal battery size for a given solar array size, taking into account reasonable day-to-day and seasonal sunlight variations as well as efficiency losses when converting from DC to AC for connection to the grid, or for provision of power during island mode. Three locations in the United States are used as case studies (Newark NJ, Boulder CO, and Tucson AZ). These provide a wide range of sunlight characteristics and illustrate variability factors that will be similar to many locations in continental North America. The analysis of the probability distributions for sunlight brightness then allow for the establishment of a 95% confidence rating for the steady-state power output from a specific combined battery and solar array configuration when faced with a grid interruption. This rating system can be used as a guide for designing systems for future installation.NOTICE: this is the author’s version of a work that was accepted for publication in Solar Energy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Solar Energy, Vol. 109, November 2014, DOI: 10.1016/j.solener.2014.08.016Peer reviewe