[wlesieutre]

Watts are a rate of one joule per second.

If you want to talk about a quantity of energy rather than a rate of energy production/consumption, the units would be either kilowatt hours or joules (1 kWh = 3,600,000 joules).

[jrockway]

Yup, kilowatt hours are a cursed unit that simply reduces to joules (a nice and easy to remember 3.6 million of them).

[wlesieutre]

Yeah I have to work that out every time