Modern Earthing systems

I do not think earthing will a big problem,  as mostly the LV side is already earthed, and the HV side is distributed without neutral or earth anyway, we are used to adding multiple sources to the grid.

At the point of generation the windings may well be earth free, but that is not important to what happens on the other side of a transformer.  (all those wooden poles with a cross bar and 3 insulators for the 11kV /33kV network carry no earth do they ?)

The bigger potential problem with wind and solar is the removal of the inertia associated with large spinning chunks of iron and copper synchronously with the grid frequency.

Most of the grid control and stability comes from the fact that frequency is a very good proxy measure of load, and that conventional generation just dips a bit in speed during short term overloads, and if any one genset is running slow, the phase angles of the current flowing change so that it's load is reduced, and in extremis, the current actually pushes the genset,  motor-like,  to get it back in step.

Electronic inverter derived AC does not do this naturally, as the voltage and cycle timing are independent, and there is no moment of inertia to borrow from in times of stress - a conventional genset can provide a few hundred percent of rated power for several cycles - electronics has to be designed to withstand that, and the controllers programmed to do it,  and getting that right may well be more of a challenge.

However once done correctly the grid should function as before, and it opens an interesting possibility..

While folk are busy designing ever more complex computer networks to meter in small intervals and control smart loads to track prices, a far simpler method seems to have been overlooked (perhaps as there is no money needed for software consultancies). If we charged more when the frequency was below 50Hz, and less when it was above, loads like heaters could contain some frequency detection electronics to wind down the load on a timescale far faster than any computerised system.

I do not think earthing will a big problem,  as mostly the LV side is already earthed, and the HV side is distributed without neutral or earth anyway, we are used to adding multiple sources to the grid.

At the point of generation the windings may well be earth free, but that is not important to what happens on the other side of a transformer.  (all those wooden poles with a cross bar and 3 insulators for the 11kV /33kV network carry no earth do they ?)

The bigger potential problem with wind and solar is the removal of the inertia associated with large spinning chunks of iron and copper synchronously with the grid frequency.

Most of the grid control and stability comes from the fact that frequency is a very good proxy measure of load, and that conventional generation just dips a bit in speed during short term overloads, and if any one genset is running slow, the phase angles of the current flowing change so that it's load is reduced, and in extremis, the current actually pushes the genset,  motor-like,  to get it back in step.

Electronic inverter derived AC does not do this naturally, as the voltage and cycle timing are independent, and there is no moment of inertia to borrow from in times of stress - a conventional genset can provide a few hundred percent of rated power for several cycles - electronics has to be designed to withstand that, and the controllers programmed to do it,  and getting that right may well be more of a challenge.

However once done correctly the grid should function as before, and it opens an interesting possibility..

While folk are busy designing ever more complex computer networks to meter in small intervals and control smart loads to track prices, a far simpler method seems to have been overlooked (perhaps as there is no money needed for software consultancies). If we charged more when the frequency was below 50Hz, and less when it was above, loads like heaters could contain some frequency detection electronics to wind down the load on a timescale far faster than any computerised system.