I have been wondering about the big line losses that are necessary in HV transmission systems , HVDC can nearly halve these to 4% but all the new renewable technology of generation and of storage is mostly DC . From the interconnector its all AC cant really change that , but if the electric car becomes reality then all the chargers will be converting DC to AC (in some quite high flows of electricity from low to full of some batteries) , so we are perhaps saying that the electric car will bring more line losses , it might not be that bigger deal, but if we electrolyse water to Hydrogen and Oxygen then the conversion losses from AC to DC will add up , so it has to be better to just transmit in DC , if we could generate in DC and I think we have brushless three phase generators now then we generate and transmit efficiently to the new big users of electricity . In the USA we see generation plant to city interconnector , I don't think they use a balancing grid , as cities are so far apart . I know any design has its problems but with the new uses of electricity any generation system will have to match (or think about the new denands) , its perfrectly possible to have designed and balanced generator to interconnector supply , but a shared transmission grid obviously allows you to arrange supply generator and demands in a different way .

One use I thought about is for a village to say have a battery and the line to it may only charge the battery once a week as DD line to DC battery and that electricity that is then spare can be used to say make Hydrogen ? It could give a completely different and more efficienct system ? Not really worked much on HV systems , but I can sort see a sketch of how it could work as a network . If only a short distance to a big demand then might as well use AC , but a 1000mw supply to an interconnector losing 7% over its life time is a lot .