Surely the benefit of low power consumption in laptop hard drives is about extending battery life, not about being eco-friendly?

Surely one leads to t'other: better battery life = longer charge intervals = less power consumed ...

One leads to the other, but it's not the motivation for lower power hard drives, as this article implied. In fact, the drive discussed is green for other reasons - it's halogen-free, according to more comprehensive reports floating about the web.

I could be massively more interested in my longer lasting battery.

I'd like to know how much power it would save, and how many more polar bears will have homes thanks to this "green" invention.