Photovoltaic is one of the products of renewable energy-based electrical energy generation technology, without using fossil fuels, even without mechanical movements in the energy conversion process. Photovoltaic depends only on photons from solar rays. The sensitivity is relatively high against the sun’s irradiance, so because of that, both the output voltage and current become unstable. However, the instability of photovoltaic in producing electricity needs to be fixed by adding power storage component, such as batteries. The purpose of this paper is to design an optimal system to measure the size of the battery in Solar Power Plant. The best sizing battery is 80MW with 194 cells.

PV output power is firmly influenced by temperature and solar irradiation that fall on the surface of the PV modules. Shading which cross-wising the surface of PV modules is major factor that prevails the degradation of its performance. The shading in PV arrays is caused by the presence of cloud, dust, fog, trees, the shadow near buildings, and so on. As the result of the shading effect, the voltage and current outputs fluctuate which would in turn reducing the efficiency of the PV output. The voltage and current of PV solar cells will drop from partial shading effect experiment which consists of 20%, 40%, 60%, 80%, and 100% shading area. This paper shows the effect of PV system over the voltage stability by variating the shading conditions using simulation by ETAP software 12.6.0.