As is becoming traditional around Bank Holidays, this is a blog sparked by a current article on the BBC website, this time about harnessing electricity from humid air.

The BBC is sceptical about the claims made by the academic, though to be fair it seems more focussed on his small-scale examples, than on the basic observation that there’s electricity in the atmosphere. My personal and network-related encounter with this phenomenon was tantalising – not because there was St Elmo’s Fire dancing about the patch panels or anything like that, but because the onset of the credit crunch sank what could have been a very nice little project.

The problem seemed perfectly simple: a company specialising in building access systems had put in a new IP-based door sensor and solenoid lock system in a Chateau down towards the south of France. As you may know, this is a rather lumpy part of the planet; the Chateau was very charming, but the grounds sloped by over a couple of hundred feet where the security and access system network spread its installations. “It’s really annoying,” said my contact. “Even when they don’t get a drop of rain or a single clap of thunder, when a cloud rolls over the place in the autumn or early spring, we will come back to find half the network melted.”

“How can that happen with fibre connections between the buildings?” I asked, and of course, my guy responded instantly: “what fibre?”

They had wired the whole site with copper, standard Category 5 cable. Another name for this is UTP, or Unshielded Twisted Pair. What the company had actually built itself was a several hundred metre wide, fine-wire antenna, buried a few inches below the surface in a few places and well connected to earth by the dampness of the soil after rain.

Even on the back of an envelope and working from my poor memory of my earnest-but-comic Welsh physics teacher’s lessons, it seemed to me that the sloping hillside was able to develop enough current in thin wires to melt them whenever a promisingly positively-charged cloud wandered overhead.

I suppose there ought to be a way to harvest this stray current, though no matter how I think about the tiny corner of the world of electrical systems design that I barely grasp, I cannot work out how to mix the functions of a fast network, a “cloudy-day current collector” and a lightning-strike proof overload protector, all together in one unit that I could strap to the back of a ten-year-old D-Link hub (for experimental deployment, you understand).

The obvious fix for the chateau, incidentally, was to bury some fibre about the place and then go looking for some cheap short-haul Gigabit interface converters to put into some second-hand, old-school mixed fibre and copper switches – but that whole project was blown away, not by a thunderstorm but by a magic money-vanishing machine.

If, that week, you had asked me to choose whether power from thin air was more likely than Icelandic banks collapsing, I would have definitely plumped for the power.