0.09 is marginal for long-term mining. It's been viable since about Febuary this year due to a massive price jump on almost all cryptocoins, but profitability has been dropping a LOT the last couple months as the price rise leveled out and more and more rigs got online to raise the difficulty - and that trend will probably continue for a while since most of the BIG farms are in places with very cheap electric (under 5c/kwh and often more like 3).
Bitcoinwisdom calculator has a "diff increase percentage" field in the calculator, which is a lot better than the "nothing" most other calculators offer.
Wow. Where do they have electricity at 0.03-0.05 per Kwh?
There are 3 counties in the USA that have 3 cent (or a little less on BIG operations) electric.
Chelan, Douglas, and Grant counties in Washington state.
Chelan and Douglas have that rate on RESIDENTIAL, Grant you have to get to the 200kw consumption level or more to get that low while residential and SMALL business rates are close to 4.5 cents/kwh
All 3 have large hydropower dam(s) they OWN on the Columbia river, with lots of excess to local needs power they sell off at a profit and roll the profits back into subsidizing local rates somewhat.
Alcoa used to have one of it's BIG Aluminum smelters in Chelan country (currently inoperative but they've been talking about PERHAPS bringing it back online), Quincy in Grant county has some fame for being the home of some GIANT server farms (Microsoft, Yahoo, Dell, and some smaller folks).
Then there are places like near the Three Rivers Dam in China that don't have enough demand (lack of infrastructure to SHIP all that electric output where it's really needed) so they sell off electric super cheap to what locals DO exist.
A few of the Middle East oil powers subsidize local electric rates too, though I dunno if they do that for non-citizens.
There are parts of Labrador, most or all of Quebec, and part of British Columbia that also have a lot of cheap hydropower available though I'm not sure if they quite make it down to 5 cents (US) per kwh at less than industrial scale rates.