@Filipe-Madureira Yes, as expected. Onion's Ethernet Expansion provides only wired 10/100 network connectivity via a standard Ethernet cable.

Power over Ethernet
Power over Ethernet or PoE describes any of several standard or ad-hoc systems which pass electric power along with data on twisted pair Ethernet cabling. This allows a single cable to provide both data connection and electric power to devices...

Here you are an example Omega PoE Dock
I think this dock is too compact, too complicated, too expensive.

If I remember well @luz has made a nice custom dock with (P)PoE capabilities - with an appropriate Ethernet jack and some ~5 .. 39V to 3.3V (or 5V) voltage converter. Unfortunetely I can't find this post.