Power management strategies and energy storage needs to increase the operability of photovoltaic plants

This paper analyzes the effect of introducing an energy storage (ES) system in an intermittent renewable energy power plant such as a photovoltaic (PV) installation. The aim of this integration is to achieve an improvement in the operability of these power plants by increasing their production predictability. This will allow a further PV integration within the electrical power system, facilitating the system's load-demand balance. In this manner, the paper proposes two power management strategies (PMSs), each with different configurations, for operating a PV power plant: the first focuses on fixing constant power production and the latter focuses on reducing the high frequency fluctuations of the production. Thereafter, this paper analyzes and quantifies the ratings of the ES system (ESS) required to ensure a reliable performance of the plant on an annual basis for each of the PMSs with their different possible configurations. The resulting ES ratings vary with these PMS configurations. It can be concluded that significant improvements in production predictability are achieved with an ESS energy capacity of approximately 50% of the average daily energy produced by the PV panels and a power rating of around 55% of the plant's rated power. All the results are based on 1-year-long simulations which used real irradiance data sampled every 2 min. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4765696]