Estimation of optimum capacity of battery by combined use of a renewable energy system and distributed emergency generators in a large hospital

Abstract

The purpose of this paper is to present an estimation method of an optimum capacity of a storage battery system by combined use of a renewable energy and emergency generators (EGs) installed in a large hospital. The hospital is planning to install a photovoltaic power generation system (PV) due to reduce a cost of the power. When the PV is installed, the battery is also to being planned for stable of the grid. However, since the battery cost is too expensive, minimization of the battery capacity based on a constraint condition of operating is required. This paper presents an estimation method of the optimum capacity of the battery to realize a stable power supply in the hospital by combined use of the PV and the EGs for island mode. As a result, the constraint condition of the battery for island operation mode is evaluated that approximately 95% of the battery capacity is the range of an arithmetic mean + two standard deviations in rainy three months.