What happened to the power costs? A few days ago they were 0.017 now they are 0.022 which is 29% increase...
1.9GH/s and 2.5W, estimated end of profitable hashing:
0.20 $/kWh - July
0.15 $/kWh - August
0.10 $/kWh - September
One month extra if BTC at $2k. From selling point, it can make wide customer base for future 28nm but needs high volume, no preorders, sell at costs, deliver on time.
How about 0.017 $/kWh