Sustainability has become an imperative requirement on many infrastructures and systems of our society with the impending energy crisis and environment deterioration.Power grids are being transformed into [http://en.wikipedia.org/wiki/Smart_grid smart grid] with advanced sensors, information and communication technologies.In smart grid, the energy flow will become two-way between the grid and consumers with renewable energy generations, which will be monitored and controlled by sensors, smart meters, digital controls and analytical tools. Smart Grid usually introduces [http://en.wikipedia.org/wiki/Demand_response Demand Response (DR)] and [http://en.wikipedia.org/wiki/Distributed_generation Distributed Generation (DG)] to improve energy consumption and generation efficiency.