The cycle analyst (ebike display) as mounted on my ebike. It’s showing the energy usage for the trip, with 27.795 watt-hours used, and an efficiency of 3.5 watt-hours per mile. 3.5 watt-hours per mile is about 2.2 watt-hours per kilometer.
https://media.hachyderm.io/media_attachments/files/111/989/912/492/720/776/original/36a774b1a7c485e2.jpg