You don't have to be in China to get very very low electric rates.
Under 5 exists in the US in a few spots, even for "residential" usage, and I'm pretty sure you can get into that ballpark in a couple areas of Canada as well.
For that matter, there are 2 counties in the US that you can get under *3* cents/kwh for residential service.
Expecting big farms to not grow when they're profitable is DUMB.
There units don't need 10 power supplies - they don't eat AS MUCH power as the S9 does and use the same number of connections.
ONE power supply per unit is entirely viable, which would be *5* power supplies and outlets for the "minimum order quantity" - I have no clue where your "10" is comming from.
At that electricity cost, it will still take 9 months plus to break even (without considering rental/staff/VAT/shipping cost). With those other costs included, it will be longer.
The risks:
-New stronger machines will come in and damage current returns. There are farms in the past that have gone offline with weaker machines like S7. There are also bankrupt mining farms like KNC.
-Warranty is only 6 months and it takes longer ot break even.
-Difficulty climbs even higher than expected due to new asic manufacturers
There is also the risk of bitcoin price going downwards and never going back up or just bursting,etc. Nothing is ever risk free. U have a higher chance of breaking even but it is not a sure thing.