To accurately predict the amount of carbon dioxide emitted.

A power generation predicting unit 113 performs predetermined simulation for hydraulic power that is non-fossil energy to generate a predicted value of hydraulic power generation capacity, and increases/decreases a planned value, corresponding to petroleum that is fossil energy according to the difference between a planned value that corresponds to hydraulic power and the hydraulic generation capacity to generate a petroleum generation capacity. An excess/shortage calculating unit 115 calculates, based on the hydraulic generation capacity, the petroleum generated capacity, a planned value corresponding to energy other than hydraulic power and petroleum and an emission basic unit corresponding to each energy; and the amount of emission by each energy and totals the calculated amounts of emission, to calculate a prediction value of emission.