In article ,
John wrote:

OK, I'll rephrase the question: why can all gens not be synced by
a common time standard instead of by the neighbouring mains
waveform?

I think because there is the unavoidable problem
of phase shift along the transmission cables. The
wavelength of 50Hz is about 6000Km, at which the
phase would have shifted a full 360 degrees.
Sounds no problem, but that represents a 10 degree
sync difference only every 167Km or 104 miles.
That might cause a problem on the UK's grid.

--
Tony Williams.