Traditional wireless and mobile network focuses on higher throughout, coverage and larger capacity. In future, energy efficiency is of vital importance for wireless networks due to a large number of connected and battery constrained mobile devices. In Long Term Evolution Advanced (LTE-Advanced), Carrier Aggregation (CA) is proposed to increase the transmission bandwidth and hence data rate. This paper studies the effect of CA on the total power transmitted by the LTE-Advanced eNodeB based on the Orthogonal Frequency Division Multiple Access (OFDMA) downlink while taking the users Quality of Service (QoS) constraints into consideration. The numerical analysis and results show that by using CA a reduction in total power consumption can be achieved.