In this work, we investigate and quantify energy savings resulting from site sleep mode without compromising coverage and QoS experienced by users. As base station sites are largely load-independent with regard to energy, we take benefit of this fact and quantify the power savings by allowing some base station sites to go into sleep mode during their low traffic periods provided their neighboring base station sites can accommodate their traffic. We propose simple controllers that are able to achieve this task while relying exclusively on local information exchanges between neighboring sites using the X2 interface. In order to evaluate energy gains in a realistic setting, we apply the proposed schemes on realistic LTE networks using traffic patterns obtained from measurements. Our results show that, in urban environments, considerable energy gains can be obtained without having to change antenna and site configuration and without compromising QoS.