In a multiple-input-multiple-output (MIMO) down-link channel, the impact of line-of-sight, out-of-cell interferers and of antenna correlation on the energy efficiency (EE) of the communication is discussed. With reference to a power budget model reflecting the power expenditure of a base station (BS) together with the power employed for training, we provide analytical insights for power control policies either designed in the presence of full channel state information (CSI) availability at the transmitter or under the assumption that power allocation does not adapt to channel state dynamically.