Donald Bell at CNet wrote
More-concrete specs are now taking shape, including an ambitiously low power rating of 1 watt per hour (compared with the 5 watts per hour required by the OLPC laptop) [my emphasis]
"Watt" is a power unit. It is defined as 1 Joule per second. Watt per hour means nothing here. From the context, the new XO-3 tablet will consume only 1 watt or 3600J per hour.
As a senior editor at CNET, Bell should have at least an elementary knowledge of science to get the units right.