That is a common mistake, but there are a lot of local areas where power is that cheap and doesn't require megawatt usage levels. If only I was lucky enough to have come from Platsburgh, NY where even the residential rate is 4.36¢ ...
https://www.electricitylocal.com/states/new-york/plattsburgh/
or Medina,OH where the industrial rate is 2.18¢!
https://www.electricitylocal.com/states/ohio/medina/
I haven't found a residential rate that low, but it is possible that the OP owns a manufacturing business that already has access to industrial level pricing.
As far as the S9 profitability, assuming that you actually do pay 3.95¢, I think there is a chance that it will still be profitable after the halving. As Phil has pointed out in other threads, there will likely be some downward pressure on the difficulty as S9s start to become unprofitable and get shut down (not that difficulty will go down, but will possible stall or increase slower). If BTC price increases, and ASIC manufactures don't flood the market with more efficient gear, and a lot of the S9s out there are burning power at >3.95¢, then maybe.... A lot of "ifs" in there though.. lol.