Real-time and decentralized energy resource allocation has become the main feature to develop for the next generation energy management system (EMS). In this paper, a minority game (MG)-based EMS (MG-EMS) is proposed for smart buildings with hybrid energy sources: main energy resource from electrical power-grid and renewable energy resource from solar photovoltaic (PV) cells. Compared to the traditional static and centralized EMS (SC-EMS), and the recent multi-agent-based EMS (MA-EMS) based on price-demand competition, our proposed MG-EMS can achieve up to 51x and 147x utilization rate improvements respectively regarding to the fairness of solar energy resource allocation. In addition, the proposed MG-EMS can also reduce peak energy demand for main power-grid by 30.6%. As such, one can significantly reduce the cost and improve the stability of micro-grid of smart buildings with a high utilization rate of solar energy.