Interesting stuff. I never realized the transmission losses of HVDC were less than AC. Though it seems like it only makes sense at very long distances because the AC/DC conversion equipment is expensive. Grounding the conversion stations also sounds very involved.
https://en.m.wikipedia.org/wiki/Pacific_DC_Intertie
https://en.m.wikipedia.org/wiki/High-voltage_direct_current
https://en.m.wikipedia.org/wiki/Pacific_DC_Intertie
https://en.m.wikipedia.org/wiki/High-voltage_direct_current