Yeah, and the article is wrong, though only slightly. They seem to be confusing watts (power, energy over time) with Joules (energy, power times a duration of time). They give a passable definition in the beginning ("energy transfer"), but they seem to misunderstand what the "transfer" part means exactly.

If you find-replace all instances of "watt" with "watt-hour" after that starting definition, it would be more accurate. That's why I say it's only slightly wrong.