Peter,

Basically provided Watts:

..."The original IEEE 802.3af-2003^[2] PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA^[3][4]) to each device.^[5] Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable.^[6]

The updated IEEE 802.3at-2009^[7] PoE standard also known as PoE+ or PoE plus, provides up to 25.5 W of power.^[8] The 2009 standard prohibits a powered device from using all four pairs for power.^[9] Some vendors have announced products that claim to be compatible with the 802.3at standard and offer up to 51 W of power over a single cable by utilizing all four pairs in the Category 5 cable.^[10]"...

https://en.wikipedia.org/wiki/Power_over_Ethernet

Aleksandra