Comment by Aachen
What is "not efficient enough"?
As a first guess, one would think it makes more sense to eat 30% loss (so you need 1/0.7=143% installed capacity) than to need 200% capacity plus batteries since it's night about half the time on average. And afaik HVDC is more on the order of ~15% loss
Aside from the physics, HVDC doesn't compete successfully on cost. It's cheaper to overbuild PV and use batteries.