Ok Odroid, you overestimated it
According to my equipment it's only 0.2 watt. I've measured it on 5V power plug. The difference between Odroid C1+ equipped with shield only and bare one is 0.04 amps. Both measurments done on 'idle' login screen with no USB device attached and max PWM value.
Since the majority of current is being consumed by LED backlight you can set PWM to half and ignore power consumption done by the shield.