The common standards for PoE:
IEEE 802.3af (PoE): Maximum 15.4W (port output), actual usable is about 12.95W.
IEEE 802.3at (PoE+): Maximum 30W (port output), actual usable is about 25.5W.
IEEE 802.3bt (PoE++): Supports higher power, such as Type3 (60W) and Type4 (90W).