With the ever increasing use of cloud computing, the need of energy also increases drastically yielding its most vulnerable adverse effects on the environment. This ultimately requires to conserve or to minimize the energy consumption laying the foundation for Green cloud Computing. In other words, Green Cloud Computing (GCC) is the data center architecture over internet whose objective is to decrease its power consumption without compromising performance from user’s perspective. A key component of Green Computing is the ability to conserve energy or reduce carbon footprints. It enables a wide range of live virtual machine migration, online monitoring, and VM placement optimization. This type of system adapts to periods of peak demand and adjusts the availability of cloud-based resources based on their expansion or contraction. Thus, this paper analyzes the extensive literature on GCC and identifies research gaps for further exploration in this area that has abundant research potential.