Alegrias1
I have to go out MaizieD. So I'll go with a question...
How do you think the analogue phone networks we use today are powered? 
I'm not being facetious but we need to look at our whole electricity usage across the board.
How do you think the analogue phone networks we use today are powered?
Well, I had thought of that, Alegrias, but I have absolutely no idea of what the comparative costs are and what the vulnerabilities of the analogue network are. I have never known the analogue network go down to such an extent that it disrupts thousands of phone lines; they seemed to survive all the 1970s power cuts without any bother. But take out a 'cloud' facility, or cut the power to it and you're talking about catastrophe...
I absolutely appreciate the arguments in favour of digital networks but we seem to be becoming dependent on technology of mind boggling complexity, coupled with people always ready, and able, to exploit any vulnerabilities for nefarious ends... this Cassandra isn't terribly confident.
But perhaps you can put my mind at rest 