Nah you're forgetting the capital to build a proper 100kw warehouse. You cant just put AC in a room and call it a day.
Also you assumed avg mining hardware is 0.7w/GH. I would say its 1w/GH due to all the rush happened when 1TH/s miner came out.
Home mining has one advantage, once you setup a mining space ( dedicated room...etc), the mining expense is only the electricity fee. At 15cent/KwH, it would be on par with 100TH mining farm's expense per TH/s
It only make sense for MW mining farms from here. All the small mining farms will close shop b4 avg home miners. Take note noobs, dont jump into any group buy hash share deals.
Capital is capital, its not a running cost. But yeah, setting up a space for 100kW means about $5,000-15,000 in electrical work and cable runs, plus $2,000-20,000 for a cooling soluton (air cooling is the cheapest)
assuming 0.7W is fair i think, since the 1w/GH gear wil very soon be balanced with 0.5w/GH, and most manufacturers are now at 0.7w/gh.
I would say that at this point in the game a 100TH farm in china (lower costs and wages) could be started up and over the salaries of two people while being profitable. In North America, you might need closer to 200TH due to the extra $15,000 year of a base salary and typically higher $/sqft for industrial space.
some basic math i did looks like 2 people with access to a suitable location costing $1200/month and needing $20,000 for setup could distribute the cost across 4 years and pay themselves a small (~30k each) salary for a 100kW/100TH farm at a cost around $30/month (a 2yr period is a cost around $50/month) Thats roughly equal to 0.05-0.08/kwh
