I never said it was a new process, I'm well aware it's been around for a long time. As for researching it, I only did a fairly cursory search as I'm not THAT interested in it to spend hours searching - and as you know a lot depends on how you word things when searching. Thank you for the links. Here in South Australia we have the most expensive electricity in the world (not bad for a supposedly First World country!) so something like this is definitely not on my agenda.