I think he may have been overly optimistic when he mentioned 15 watts - I wish mine only consumed that much power!
Having said that, it’s good that he’s taken the step towards becoming more energy efficient. There are much lower power machines and monitors available on the market, and if every office in the world were to use them and adopt greener strategies to save power, well, you can imagine just how much energy would be saved.
The number of office lights and PC’s still on at night is alarming, though I think more people are making a bigger deal about this and crucially turning off machines when not in use.