In Japan a feed-in tariff scheme has promoted the utilization of photovoltaic power generators in combination with electric batteries. Although many researchers have assessed the operations of grid-connected photovoltaic systems with electric batteries, little attention has been paid to the impact of the electric batteries' degradation characteristics. This paper presents an evaluation of the operation of a grid-connected photovoltaic/electric battery system in a house from energy saving and economy viewpoints. We constructed a long-term operational optimization model considering the degradation characteristics of the electric battery. This model contains two objective functions: energy saving and operating cost. We set a scenario of power rate and photovoltaic/battery system configurations. In order to reveal the optimal operational strategy of the photovoltaic/battery system, the multi-objective optimization problem was solved. As a result, pareto optimal solutions were obtained, and trade-off relationships between economy and energy saving are presented. In this study, the utilization of the grid-connected photovoltaic system with an electric battery was expected to be effective in an energy saving priority operation.