I was also watching this and it's quite interesting to see what will happen. I heard from many farms that they have shut down the miners as long as it's not profitable to mine and switch on the miners again when electricity prices can be covered. But BTC price needs to increase to a sufficient limit to avoid switching miners off and on all the time when the price keeps being volatile.
Right now the electricity price should be cheaper than around 0.05$ kWh to cover electricity and maintenance. For sure it depends also on salaries for employees which are very different depending on the country. But getting more BTC after paying employees and electricity is not the final calculation. The latest ASICs last only for a few years. If it's not possible to get your ROI during this period of time, you are also mining at a loss because ASICs are not free. In most cases you need for a lifetime of 2 to 3 years per miner a ROI of 33% to 50% per year. ROI calculated in BTC.
I posted this table a few weeks ago in the german section and now we are at a level from late July. The next difficulty adjustment seems to be also getting down.
Time Difficulty change average block time 2018-12-03 12:59:28 5,646,403,851,534 - 5.65 T
- 15.13 % 11 min 47 s
2018-11-17 00:51:24 6,653,303,141,405 - 6.65 T
- 7.39 % 10 min 48 s
2018-11-01 21:54:16 7,184,404,942,701 - 7.18 T + 0.02 % 10 min 00 s
2018-10-18 20:37:47 7,182,852,313,938 - 7.18 T
- 3.65 % 10 min 23 s
2018-10-04 09:49:22 7,454,968,648,263 - 7.45 T + 4.23 % 09 min 36 s
2018-09-20 23:15:39 7,152,633,351,906 - 7.15 T + 1.90 % 09 min 49 s
2018-09-07 05:14:39 7,019,199,231,177 - 7.02 T + 4.34 % 09 min 36 s
2018-08-24 18:50:31 6,727,225,469,722 - 6.73 T + 5.29 % 09 min 30 s
2018-08-11 11:40:59 6,389,316,883,511 - 6.39 T + 7.39 % 09 min 20 s
2018-07-29 10:19:31 5,949,437,371,609 - 5.95 T + 14.88 % 08 min 42 s
2018-07-17 05:50:49 5,178,671,069,072 - 5.18 T
- 3.45 % 10 min 22 s
2018-07-02 17:34:21 5,363,678,461,481 - 5.36 T + 5.64 % 09 min 28 s
2018-06-19 11:20:45 5,077,499,034,879 - 5.08 T + 2.77 % 09 min 44 s
2018-06-05 20:18:06 4,940,704,885,521 - 4.94 T + 14.71 % 08 min 43 s
2018-05-24 15:20:53 4,306,949,573,981 - 4.31 T + 3.94 % 09 min 38 s
2018-05-11 03:54:15 4,143,878,474,754 - 4.14 T + 3.03 % 09 min 43 s
2018-04-27 13:24:13 4,022,059,196,164 - 4.02 T + 4.76 % 09 min 33 s
2018-04-14 04:28:52 3,839,316,899,029 - 3.84 T + 9.35 % 09 min 09 s
2018-04-01 09:05:57 3,511,060,552,899 - 3.51 T + 1.40 % 09 min 52 s
2018-03-18 12:40:18 3,462,542,391,191 - 3.46 T + 5.23 % 09 min 30 s
2018-03-05 05:21:18 3,290,605,988,755 - 3.29 T + 9.42 % 09 min 10 s
2018-02-20 09:20:59 3,007,383,866,429 - 3.01 T + 4.62 % 09 min 34 s
2018-02-07 00:08:07 2,874,674,234,415 - 2.87 T + 10.43 % 09 min 03 s
2018-01-25 07:48:20 2,603,077,300,218 - 2.60 T + 16.84 % 08 min 34 s
2018-01-13 08:12:34 2,227,847,638,503 - 2.23 T + 15.36 % 08 min 40 s
2018-01-01 04:56:10 1,931,136,454,487 - 1.93 T + 3.10 % 09 min 42 s
2017-12-18 14:55:20 1,873,105,475,221 - 1.87 T + 17.74 % 08 min 30 s
2017-12-06 17:23:21 1,590,896,927,258 - 1.59 T + 18.11 % 08 min 28 s
2017-11-24 20:53:16 1,347,001,430,558 - 1.35 T
- 1.28 % 10 min 08 s
2017-11-10 16:13:51 1,364,422,081,125 - 1.36 T
- 6.09 % 10 min 40 s
2017-10-26 18:52:42 1,452,839,779,145 - 1.45 T + 21.39 % 08 min 14 s
2017-10-15 06:05:02 1,196,792,694,098 - 1.20 T + 6.49 % 09 min 24 s
2017-10-02 02:27:46 1,123,863,285,132 - 1.12 T + 1.85 % 09 min 49 s
2017-09-18 08:31:16 1,103,400,932,964 - 1.10 T + 19.58 % 08 min 22 s
2017-09-06 15:23:15 922,724,699,725 - 922.72 G + 3.89 % 09 min 38 s
2017-08-24 03:57:37 888,171,856,257 - 888.17 G
- 3.80 % 10 min 24 s
2017-08-09 14:36:50 923,233,068,448 - 923.23 G + 7.32 % 09 min 20 s
2017-07-27 13:03:54 860,221,984,436 - 860.22 G + 6.92 % 09 min 21 s
source: BTC.comI don't know any official numbers but it makes sense that low BTC prices are better for large mining farms because they have often very cheap electricity and after all very low maintenance costs due to their large scale operations.
It will be interesting to see how things will proceed when BTC will go to previous highs or at least to 10,000$. My expectation is a much higher difficulty than before the recent drop because all of them are only waiting to switch on their miners again.
I read an
article on that yesterday and it posits that a drop in hashrate means it would take longer for new blocks to be found.
This should not be a problem, the difficulty is adjusted every 2016 blocks (around 2 weeks) to keep the blocktime close around 10 minutes. If the hashrate decreases during a 2016 block period, the difficulty will also decrease next difficulty adjustment.
You can see it as
average block time in the table