With increased attention of renewable energy, large-scale installation of photovoltaic (PV) generation and electricity storage is expected to be installed into the power system in Japan. In this situation, we need to keep supply-demand balance by systematically using traditional power generation systems as well as the PV generation and storage equipment. Towards this balancing, a number of prediction methods for PV generation and demand have been developed in literature. However, such prediction-based balancing is not necessarily easy. This is because the prediction of PV generation and demand inevitably includes some uncertainty. Against this background, we formulate a problem to plan battery charge cycles while minimizing the fuel cost of generators with explicit consideration of prediction uncertainty. In this problem, given as parameter-dependent quadratic programming, the prediction uncertainty is described as a parameter in constraint condition. Furthermore, we propose a method to find a solution to this problem from the viewpoint of monotonicity analysis. Finally, by numerical analysis based on this problem and its solution method, we discuss the relation between the minimal reserve generating capacity and the required battery charge/discharge cycles to tolerate a given amount of prediction uncertainty.