Hi,
this is not specified because it depends also on external loads. But if we consider that max current consumption of the microcontroller is roughly 60mA, current consumption of rest of the board won't be more than a few tens of mA. And if you connect some external circuits to the pin headers than it also won't be so significant. In this case, adapter 12V/1.5mA is more than enough.
Regards,
Lukas
