Provided is a control device of a home energy management system (HEMS). The control device includes a communication unit configured to connect to a HEMS gateway, a storage unit configured to store power usage information for a predetermined period in a home in which the HEMS gateway is installed, and a control unit configured to predict power consumption amount on the basis of the power usage information for the predetermined period, predict a power generation amount of a photovoltaic (PV) module connected to the HEMS gateway, calculate a PV power amount to be sold on the basis of the predicted power generation amount and power consumption amount, set sales price with respect to the calculated power amount on the basis of purchase information of purchasers, and control the HEMS so that sale power corresponding to the calculated power amount is provided on the basis of the set sales price.