Energy comes in many forms, and the main choice between them can be made on the basis of public image, rather than the best result. 

A few months back we had the brouhaha over Facebook's use of coal-generated electricity in its data centers, which turned out to be the same source of energy that its critic, Greenpeace uses. Since then we've had data centers powered by cow manure - which turned out to be a theoretical paper, and not exactly a practical proposition, according to fellow blogger Doug Mohney. 

More seriously, Google and other providers are buying into wind energy, which strikes me as a practical proposition, and one which in the UK, BT has been planning to do. There was a fear that new regulations, the UK's carbon reduction commitment (CRC) might actually have an unintended result in making BT's wind farms uneconomical, but that threat seems to have receded for now, according to my latest talks with the company. 

As I've said before, we can expect this sort of thing, since we are trying to push green power beyond its current natural economic viability, in order to save a resource with no financial value - the planet. We set up a system, and it will be gamed. 

In amongst all those heavy, sensible stories, I have to say I was delighted to come across a novel "green power" idea with - I have to admit - very little obvious application to data centers. 

UK mobile operator Orange makes a habit of coming up with a funky "green" idea for the UK's "festival" season (for those like me who spend too much time in darkened rooms, "festival" is an outdoor festival of music and usually mud, typified by Glastonbury). It's a publicity stunt, plain and simple, but I like it. In the past, it's offered  solar cells built into a tent, a dance-mat powered by kinetic energy, and other things. 

This year, the idea has the right level of gritty reality. People at festivals encounter mud, and wear boots. So Orange is offering rubber boots ("wellingtons") which generate what Orange calls "welectricity", from the thermal gradient that is set up between feet which have heated up through energetic dancing (or slogging around looking for a usable toilet), and the cold slime of mud that surrounds them. 

Like so many renewable sources, the yield isn't that great - apparently it will take about ten hours to generate enough power for one hour of talk - and you will need all that to boast about your renewable energy boots. 

But every little helps, right? And it's not that easy to find anywhere to plug a charger on a campsite. 

But maybe I was wrong about their applicability in the world of green data centers. If your data center is run on cow manure, these boots could be just the thing!