"Energy-Assisted" is an umbrella term for HAMR and MAMR drives. This is really
the announcement of their new Ultrastar DC HC550 drives, which are non-SMR Heat
Assisted Magnetic Recording (HAMR) drives, non-SMR (as in, not shingled). Good
for around 550TB/year, thus the name, presumably. They also feature a bunch of
fancy datacenter-class features like top and bottom (7200rpm) motors, top and
bottom disk clamps, RVFF sensors, humidity sensors, etc.
But, I kind of buried the lede here because the interesting part is the
capacities which are both nine platter and clock in at 16 and 18TB.