In order for Wake-on-LAN to work, parts of the network interface need to stay on. This consumes a small amount of standby power, much less than normal operating power. The link speed is usually reduced to the lowest possible speed to not waste power (e.g. a Gigabit Ethernet NIC maintains only a 10 Mbit/s link). Disabling wake-on-LAN when not needed, can very slightly reduce power consumption on computers that are switched off but still plugged into a power socket. The power drain becomes a consideration on battery powered devices such as laptops as this can deplete the battery even when the device is completely shut down.