Saving the world on 5p a year.

As a dynamic entrepreneur, one thing that my company does is supply of a lot of information on things like energy efficiency and carbon reduction to industrial users. In many ways this is great - not only does it allow me to adopt the pious, holier-than-thou aspect of the committed green, but I can claim to be actually doing something more than spouting platitudes and driving or flying long distances to go on protests like many advocates of the green movement I've met.
As I'm always looking for more ways to add a touch of sparkle to my eco-halo, I was considering buying one of the salor rechargers for my phone. Presumably you know the sort of thing, and about £13 isn't much money. Just to make sure I was getting good value for money, I then went and looked at how much electricity it takes to fully charge the average mobile phone battery - and was surprised that it takes approximately 1/400th of a standard unit of electricity. Assuming that a single unit (1kW/h) costs about 10p (and that's a high assumption - it's more like 4-5p, but I'm working on high assumptions just to be sure) it costs about 0.025p to charge my phone. Further assuming that I charge my phone twice a week and this includes a 100% inefficiency, this works out at about 5p a year to charge my phone.
To put it another way, it'd take the solar charger at least 260 years to pay for itself, and that's not taking into account the carbon/energy costs of manufacture and shipping the device itself.

Sometimes being green just isn't worth it.