The data I've found from some quick googling [1] indicates a power consumption of around 5 watts at idle, with the LCD backlight dimmed to 40 percent brightness, with power ranging from there up to about 12-15 watts at load.
From experience, the 13 inch Intel laptops I've used recently burn about the same at idle, and don't consume much more for basic tasks, especially e.g. hardware accelerated video decoding.
The other thing to consider is that they're much faster than the pinebook while consuming equal amounts of power, therefore using less electricity overall since you're waiting less time for the CPU to idle down (assuming you're not pegging the CPU at full load, which is harder and harder to avoid with JavaScript event loops running everywhere...)
All that to say, a slower/worse computer =/= a more energy efficient one. Although it probably does build the "software discipline" you need to use energy efficient software ;)
[1] https://gist.github.com/ayufan/1075c3c48ad3e9c7928334c99f7b3...