Cloud radio access network (C-RAN) has been shown to reduce both capital and operating expenditures and provide high spectral efficiency (SE) and energy efficiency (EE). High density of remote radio heads (RRHs) deployments results in inefficient energy consumption. Moreover improvements in the battery capacity of mobile devices lag far behind the surging demand for transmit power, which makes power efficient communication an essential requirement for the next generation wireless communication systems. In this paper we consider a network with multiple service providers share the ultra-dense C-RAN (UD-CRAN). We consider the QoS requirement of each service provider and propose power control algorithm. The performance is evaluated through simulations and demonstrated that our algorithm provides significant energy efficiency gains while meeting the given data rate specifications.