Why do we need a new coast to coast supergrid?

One estimate I remember reading claimed that with renewable smart grid technology and using distributed generation and storage and energy conservation, existing cables and transmission equipment already has 5 times the capacity which would eventually be needed.

For instance: those electric vehicle batteries would actually reduce necessary grid capacity if they could be used for distributed storage when they are parked, either at home or at work. And switching the air conditioning load to ground source cooling (as well as the huge heating loads in winter) would vastly reduce load.

Smart grid timing of high load devices like water heaters and freezers would likewise reduce peak demand. then the existing local grid capacity would be more than enough. But there would still need to be a high voltage diect current "electron superhighway" backbone to transport renewable energy surplus across the continent to ameliorate the varying availability of wind and sun and water power.

In other words, concentrate on a national high voltage smart grid and we could avoid the even more expensive wholesale replacement of all those local power cables and transformers and switches.

I'm looking forward to your discussion of an HVDC continental smart grid with superconducting electromagnetic storage Amanda. It is essential to get wind, water, and solar power investors to get a return on their money with efficient transportation of southwestern solar power and coastal and offshore wind and water power, and wind and biomass power from the midwest, from areas with excess supply to areas with high demand that coincides with insufficient local/regional renewable energy supply.