There are tons of HVDC interconnects and transmission lines in place, many of which are already over 1000 km long. Many of these projects have been in place for

There are tons of HVDC interconnects and transmission lines in place, many of which are already over 1000 km long. Many of these projects have been in place for decades. Breakthroughs in solid state HVDC are making it easier and cheaper all the time, but it's not some fanciful science fiction technology. It's a key element of existing power grids already. https://en.wikipedia.org/wiki/List_of_HVDC_projects https://en.wikipedia.org/wiki/List_of_HVDC_projects