I think eventually this problem will be solved mostly by reducing transportation distances as solar will be wider distributed so on average power will travel a

I think eventually this problem will be solved mostly by reducing transportation distances as solar will be wider distributed so on average power will travel a shorter distance. It's not some terribly fantastic amounts of power we are talking about. Full decarbonisation of EU will need only about 5x more renewable electricity than today. In any case, 2050 plan does not call for any drastic increase in transmission capacity. Don't forget that power output from hydro can be greatly increased if needed - total amount of energy produced can't because water in dams is finite - but peak power can be increased rather cheaply.