OPEX would be about 20-30% cheaper for me
What exactly are you comparing?
I'm in a densely populated, high electric cost area. The tanks would look much better if I lived, say, in Washington state.
If you are in a densely populated area 6 tanks with 1.2MW total would take a lot less space than dozens of racks?
And in a place like Washington with $0.02/kWh cooling would be relatively small, no matter you pay a lot or a little?
Sorry, looks like I fat fingered the calculation - redone it and it shows the OPEX in a DC to be about 2.25x that of the tank!
But that includes rent and 24/7 security, which is not included in the OPEX of the tank (and I have no idea how much it would be for good 24/7 security).
Electricity here is ten times the cost of a place like Washington state but the rent is only about double (by the looks of it). Depending how big your racks are, the rent might not play too big a role or even be cheaper here (you can stack more than with containers/tanks). Containers look like the 40ft type.
Also, it is probably easier and faster to deploy 55 racks in a DC (already setup, not owned, because of the 2-3x reduction in electricity costs) than a tank here, and that's also to consider for bitcoin. Of course, after you have your massive electricity installation deployed, it's another story. (you can't get that much power everywhere and it costs a good amount of money to install the necessary transformers and a few months before actual deployment)
So, meh. For now.