Great marketing spin
I can't imagine that I am the only person to notice the obvious marketing spin in this statement from HP:
"HP also claimed a green hue. Its new LTO-4 Ultrium 1840 tape drive consumes 50 per cent fewer watts per gigabyte than previous gear"
For those that missed it (including the usally very sharp Reg staff) LTO-4 technology offers twice the capacity of LTO-3 so it's probably not all that suprising that new LTO-4 drives (from HP or anyone else) consume 50% fewer watts per gigabyte.
In essence this statement just says that HPs new LTO-4 drives use exactly the same amount of power as their old ones, which hardly represents a step towards greener computing but no doubt looks impressive on a press release.