That $15M figure is wildly speculative, and assumes an average wattage per gigahash that's more in line with the state of mining as much as 2 years ago, when GP

That $15M figure is wildly speculative, and assumes an average wattage per gigahash that's more in line with the state of mining as much as 2 years ago, when GPUs dominated mining. ASIC units (like my 14.5GH/s from two BFL units which pull less than 50W together) are far more efficient than the quoted 650W per gigahash, by up to two orders of magnitude, which would push the average for the whole network far below break-even.