Roughly 45 older mining devices have been shut down overnight since the reward halving. The estimate of the 45 miners is based on the electrical price of 0.35 Chinese yuan per kilowatt-hour (kWh) or $0.049 USD.
The best mining device out of the entire slew of ‘unprofitable’ mining rigs would be Bitmain’s Antminer S11 (20.5 TH/s), which still loses $0.09 per day at $0.049 per kWh. Other machines that are not making profits at this rate, include the Bitfury Tardis, Antminer S9 SE, GMO Miner B2, Innosilicon T2 Turbo, Bitfily Snow Panther B1, Canaan Avalonminer 921, and the popular Antminer S9.
Research analyst and 8btc columnist Vincent He did an analysis on this. The data showed that at $0.049 per kWh, Bitfury’s B8 released in 2017 with 49 TH/s, suffers a deep loss of more than $3 a day.
The Chinese mining operation F2pool states “Now, only when the price of the bitcoin rises to $15,000, can Antminer S9 cover the cost. In the past, even if there were a mining disaster and the price dump of the mining machine, someone would still buy S9. Most of the recipients are the owners of large mining farms. When the bitcoin price recovers, they can mine it by themselves or sell it to others to earn the difference.”