The electrical power system is technologically making advances at a very fast pace and virtual power plants is an outcome of this advancements. Virtual Power Plants (VPPs) are a collection of generators (conventional, renewable or distributed), flexible loads and storage systems or a combination of any of these. It is a centralized controlled entity with no physical boundaries. VPP is classified based on its area of operation and services provided. It acts as an excellent player in the energy markets and is marked for bringing in flexibility in the system. This chapter introduces the basic concepts of VPP, its definitions and different control structures. It also presents a detailed comparison of VPP with Microgrid. It also lists a number of real-world VPP projects around the world based.