Methodology for calculating the lifetime of storage batteries in autonomous energy systems with renewable power generation

Abstract

This paper presents a versatile and simple methodology for calculating the lifetime of storage batteries in autonomous energy systems with renewable power generation. A description is given of battery categorization and its importance in establishing potential configuration options.Battery operating modes are modeled using the chronological modeling method which defines the mode indicators with respect to every hour of the period under consideration. The notions of partial cycle and local minimum state of battery charge are introduced. These indicators are necessary for the correct estimate of the number of battery cycles to failure. After identifying the number of cycles to failure and the average annual number of cycles, it is possible to calculate storage battery lifetime.This methodology was used in 2014 when designing and setting up Verkhnyaya Amga, a photovoltaic system in the Republic of Yakutia (Russia’s Far East). The results showed that it is best to use lead–carbon batteries with a total capacity of 144 kW h.

Keywords

• Renewable energy source
• Storage batteries
• Photovoltaic system
• Autonomous power supply system
• Full and partial charge/discharge cycle
• Cycle life vs. depth of discharge