In article ,
Rod writes:

Mention of HVDC reminds me that the Channel link is one such (at least,
I think that's what I remember). So that prompts me to ask, how closely
synchronised are the UK and France, and indeed the other European countries
with each other?

(Hope I haven't missed this question somewhere else in this huge
thread!)

I haven't seen a synchronisation map since the Berlin wall came down.
However, before that, most of Western Continental Europe was a single
zone controlled from Switzerland, Eastern Europe was controlled from
Moscow (can't recall if it was a single zone) and Great Britain was
its own synchronisation zone controlled from Reading, Berkshire.

When the Berlin wall came down, West Berlin was very short of power
and had been suffering power cuts as a result. East Berlin had a
surpless but it was produced by horribly poluting power stations.
They couldn't be easily linked as they were in different synchronisation
zones. Also, whilst West Berlin was 50Hz +- 0.5Hz, East Berlin's
frequency varied by considerably more than that. I don't know how this
was eventually resolved -- I read about it only a few months after the
wall came down and there was no resolution at that time. Lots of UK
power (and gas) engineers got contracted out to the former East Germany
just after unification as part of a massive repair of their broken
infrastructure (loads of leaking gas mains was a serious problem).

--
Andrew Gabriel