Cloud computing offers variety of resources and provides flexible services to users. The major issue ominous cloud computing is that it consumes servile amount of energy for providing a valuable computing services. Many attempts were taken to decrease the energy consumption of the data center yet the endeavors make less satisfaction. In this paper, a survey of energy consumption in the cloud computing is described a) Problems in the existing methods and energy reduction constraint used by various algorithms b) Comparison of various techniques with their findings emphasizing their advantages and disadvantages. Resource allocation in cloud is another issue in which energy can be reduced, and if a server is in idle it menaces enormous amount of energy and many algorithms were attempted to make the idle server to use in an efficient manner. Cooling of data center is also another enticing issue, because during heat the server consumes more energy and the stability of the system is reduced. Finally, the objective is to decrease the amount of energy consumed in data center leading to enhancement of Quality of Services (QoS). © 2017, Walailak University. All rights reserved.