If I remember correctly ZFS keeps the whole array running whenever one is active (which is basically always). If I remember, I’ll check my UPS when I get home to see the actual power draw. The storage itself is probably cheaper to run than the main server in the rack - a gen8 HP 360p, which is a bit on the old side and I’d guess not terribly efficient being a 1U piece with many small high-powered fans running constantly.

Electricity here isn’t too expensive though, being public hydro power.

That’s a slight exaggeration. I think it was about 2 years to get close to filling that up. Keep in mind that a chunk of that is unusable due to drive parity.

It really depends on what you’re doing. In my case the soft costs like domains are pretty negligible compared to how much I seem to spend on more hard disks every six months. You might tell yourself, “96 TB of raw storage will last forever,” but it turns out forever is about a year.