If the projected difficulty cut takes effect, Bitcoin miners could earn about 7% more per unit of computing power. But the relief would still leave two older S19 models needing electricity to cost close to 4 cents per kilowatt-hour just to cover the machines’ power use.
In its November 9 snapshot, timestamped 18:00 UTC, Hashrate Index projected a 6.5% difficulty reduction around November 13. The mining data platform put current difficulty at 148.36 trillion and spot hashprice at $31.89 per petahash per second per day. Hashprice is the expected daily revenue from a unit of mining capacity, before expenses.
Assuming Bitcoin’s price, block subsidy and average transaction fees per block remain unchanged, the projected cut would raise hashprice to about $34.11. It would give miners still operating more room to cover electricity costs, but a substantial gap would remain between older equipment and a more efficient S21.
When difficulty falls, a given amount of computing work has a higher probability of earning a block reward. If reward value remains fixed, expected revenue per unit of work therefore rises as difficulty falls.
The scenario calculation divides $31.89 by 0.935, the portion of difficulty remaining after a 6.5% reduction. The result is a 7% increase, isolating the effect of the retarget. Actual dollar receipts would also depend on Bitcoin’s price and fees.
Bitcoin adjusts difficulty every 2,016 blocks, using block timestamps to target a period of roughly two weeks. The estimated November 13 adjustment date and the projected size of the cut could change as more blocks are mined.
Older rigs still need cheaper power
A useful operating measure is the maximum electricity tariff that gross mining revenue can cover. Dividing expected daily receipts by a machine’s daily wall-power consumption gives this electricity-only ceiling. Below the ceiling, some revenue remains for other expenses; above it, the machine’s electricity bill alone exceeds gross revenue.
BITMAIN lists two S19 model 240-Ca variants in its specifications: one at 95 and the other at 90 terahashes per second. Both have a nominal power draw of 3,250 watts at 25 degrees Celsius. The S21 specification lists 200 TH/s at 3,500 watts under the same temperature condition.
| Nominal model | Hashrate | Wall power | Nov. 9 electricity ceiling, cents/kWh | With projected cut, cents/kWh |
|---|---|---|---|---|
| S19 240-Ca | 95 TH/s | 3,250 W | 3.88 | 4.15 |
| S19 240-Ca | 90 TH/s | 3,250 W | 3.68 | 3.94 |
| S21 | 200 TH/s | 3,500 W | 7.59 | 8.12 |
The calculations assume continuous operation at nominal ratings and a 6.5% difficulty cut, while Bitcoin’s price, subsidy and average fees per block stay unchanged. They exclude pool fees, separate cooling and site loads, repairs, labor, hosting overhead, financing and equipment costs.
At an illustrative tariff of 5 cents per kilowatt-hour, both S19 variants would still bring in less than their electricity costs after the cut. A nominal S21 paying 8 cents per kilowatt-hour would go from falling short to just covering electricity, with a thin cushion of about 10 cents a day before other costs. The two tariffs are illustrative.
The comparison uses each model’s stated power draw and hashrate. Individual machines may differ: BITMAIN gives the S19 variants a hashrate tolerance of plus or minus 3% and a wall-power tolerance of plus or minus 5%. The S21 specification gives no numeric tolerance. Each ceiling applies to the specific model and nominal settings shown.
CryptoSlate’s October 14 analysis modeled the electricity squeeze under a projected difficulty increase. Its November 4 report examined a forward market that implied little additional mining competition.
The next test will be the completed adjustment and the hashprice that follows. Using the November 9 inputs, the projected cut would broaden electricity coverage. Whether that translates into a viable operating margin will depend on the actual revenue rate, equipment performance and costs beyond the machine’s power draw.
Source: cryptoslate.com. Adapted by NBTC.
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