Move it all via DC and water cool the cables, far more efficient for long distance power transfer, the same output as solar and batteries and with steam turbines being phased out over the next however many yrs, only gas, hydro and wind turbines will be AC, so not the huge costs involved converting from AC to DC where needed, gas being peak load supply, it would go straight into the local network as would the hydro, wind would be used locally as required and the rest converted to DC to be distributed around the nation.
It would open up the prospects for huge geothermal/solar thermal salt water lake based heat storage to provide that much talked about, base load power.
Include the freight rail corridor and use DC locomotives to utilise the energy already travelling through the tunnels and be able to regen back into the grid for braking ......
It's not that they have always done the AC route in the past, so they won't change, they already do it, so it's not something new that they know nothing about ......
T1 Terry