I have been struck by the increasing number of appliances, both in the home and in the office, that operate at low voltages (12V or less) and not at the 110V or 230V mains outlet voltage. The vast majority of these appliances are powered by what are obviously very cheap, poorly designed power units, which are usually left plugged-in whether the appliance is in use or not.

As an example, look at mobile phone charging units, or the power supplies for laptops. Most of us leave the chargers plugged in permanently, whether we are making use of the appliance or not. And when I mean, poorly designed, try touching the unit when it's not delivering power, but plugged in. In most of them, you'll easily feel the residual warmth, resulting from the poor design (with cost being put before energy efficiency).

My thought was really, isn't there a better way of distributing low-voltage power? I concede that replacing mains distribution networks with 12V networks isn't on. You probably don't want to start distribution 12V power over any distance greater than say 5 to 10 m, but that would be feasible in a number of places. To supply the 12V power, you would use high quality power units, which would shut down or run on trickle power when not delivering power. You would need fewer of these to replace all the cheap inefficient power units in use today.

An alternative would be to have special units delivering 12V power in exactly that fashion. They probably wouldn't be very big, and it would resolve the problem of how to plug in multiple transformers side by side into mains outlets, something which is practically impossible to do today.

Of course this would require agreement on standards on voltages, low-voltage plugs and sockets and installation practice to allow all this to happen, but I am convinced that replacing the inefficient means we have today of supplying power to all the electronic devices we have in our homes and offices by new technology could significantly contribute to improved energy efficiency of these appliances.