March 29th, 2008 at 02:29pm
Plenty of people think I’ve gone near-enough to completely mad with my post about turning on all of my lights during Earth Hour…somehow I don’t think the organisers would mind as it just proves that even people such as me who see almost no sense in the theory of anthropogenic global warming are thinking about Earth Hour and giving it more publicity.
Anyway, the reason for this post isn’t to try and convince people that I am sane, rather it is to show the perspective of Michael Carden, somebody who has spent an awful lot of time fixing broken electronic devices.
Most modern pieces of electronics make use of a switchmode power supply. Everything from TVs and DVD players, to computers and kitchen appliances are likely to have one, and in general they are a wonderful thing. Small, light, cheap and able to run from the mains power in most parts of the world without caring whether they’re plugged into 110, 115, 150, 230 or 240 volts. They (mostly) just work.
If you have this device plugged into power all the time, a small part of its switchmode power supply – the part responsible for kickstarting it from completely off – never gets used. And this part almost always contains a handful of tiny electrolytic capacitors that play no part in the running of the device until it’s disconnected from the power outlet, and then connected again. Then it’s their job to get the power supply started. These little beasties don’t like heat very much, but they usually live in a hot place (the switchmode power supply) and so as the months and years go by, the heat slowly kills them. They can die completely and you’ll never know. Unless you unplug the device or switch off the power outlet.
So I’m wondering what will happen if thousands or millions of people switch off everything at the power outlet all at once. I think that there’s an excellent chance that quite a lot of stuff won’t come back to life when the power goes back on.
Michael goes on to point out that the percentage will be quite low, but if you’ve never turned off the microwave, the DVD player or the cordless phone at the wall, so you really want to risk it?
My other thought on the subject is this. The electricity suppliers have their systems set up to expect a certain minimum load that never goes away. While I’m sure that their systems are designed to cope safely with the sudden loss of load when everyone switches off, I can’t help but wonder just when they tested this.
Hmmm, it’s one thing to be voluntarily without power for an hour, with a switch to turn it back on at any time a couple metres away, but if enough people take part in Earth Hour and something does go “bang” in the power grid, how many people are actually going to enjoy Earth Week?