This read-only Unsigned32, in joules per its source description, reports the energy this PoE port supplied to its attached device over the past hour, automatically updated at that interval. Admins use this hourly figure for capacity planning and energy-cost estimation across the PoE deployment, aggregating it with other ports' hourly figures to estimate total power draw. For example, multiplying this hourly joule figure across all active PoE ports would let an admin estimate the switch's total PoE energy cost for a full day.