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Field report · Sep 30, 2026 · 3 min read

Hashprice nearly halved, and the Antminer S21 Hyd still cleared its power every month

Bought in June 2024 at a settled price, a hydro-cooled 16 J/TH machine has sat in our UAE site ever since. Hashprice fell 47% to the lowest reading in our daily record, and not one month failed to cover its electricity. Here is what it has banked and what is left in it.

A Bitmain Antminer S21 Hyd in front of a blurred row of dry coolers at dusk

Bitmain Antminer S21 Hyd (335 TH/s)

Two months after the halving, at $52.48 a petahash

The Antminer S21 Hyd is a water-cooled machine rated at 335 TH/s and 16 J/TH, drawing 5,360 W. We bought ours on 18 June 2024 at $6,402, and landed it at $8,192 at our UAE site: the one we build around water, with a dedicated hydro plant, better than 99% uptime and a manufacturer warranty centre close by.

It started hashing two months after the halving, which cut the subsidy from 6.25 to 3.125 bitcoin at block 840,000 on 20 April 2024. That left no pre-halving months to bank. On 18 June 2024 hashprice, the dollars one petahash of hashrate earns in a day, was $52.48.

Everything since has been the network catching up. Difficulty went from 83.7 trillion on 18 June 2024 to 132.8 trillion on 29 September 2026, a rise of 59%. Bitcoin rose too, from $65,183 to $83,471, but not enough to hold hashprice up.

Chart: Hashprice in dollars per petahash per day since the month we bought, with the bitcoin price overlaid. Bitcoin climbed; hashprice still drifted down to the trough of June 2026. Open the chart

Hashprice fell 47% and no month failed to cover the power

The bottom came on 6 June 2026, when hashprice touched $27.74. That is 47% below where it stood the day we bought, and the lowest reading in our daily series, which starts in 2013. It is the test a 16 J/TH machine was bought to pass.

It passed. In every calendar month of its run, including that June, its coins were worth more than the electricity that made them. The thinnest months were all in 2026, when hashprice sat closest to its floor; the best were in late 2024 and mid-2025.

It sat above the power line at the worst reading in our daily record.

Chart: Profit over electricity, month by month, at the UAE site where it has run throughout. Every bar is above zero, and the shortest ones are the months around the June 2026 low.

Sixteen watts a terahash was enough at 6¢

The reason is the power line. A machine at 16 J/TH draws 16 watts for every terahash it runs, and at the June low one petahash's day paid enough to cover electricity of about 7¢ a kilowatt-hour. Our UAE rate is 6¢.

That is a thin margin, not a comfortable one, and it is what efficiency decides: how far below the line a machine sits when the market is at its worst. At 16 J/TH this one sat below it all the way through.

Chart: The electricity price at which each class of machine breaks even, from 13.5 to 29.5 J/TH, against our site rates (dashed). A 16 J/TH machine sits between the first two lines. Open the chart

A coin costs it more than it did, and it has not left the UAE

In July 2024, its first full month, a coin cost the machine about $31,600 of electricity. That climbed to about $60,800 in November 2025 as difficulty rose and hashprice sank. Today it is about $52,700, against bitcoin at $83,631.

Over the whole run the average is $46,500 a coin. Treat that as history: the number to plan on is today's.

Nigeria would make the same coin for about $34,200, because power there costs a third less. Its uptime is lower, 73.6% against the UAE's 99.3% on our sites page, so it mines fewer coins a day. The rule is to cross to Nigeria once, when a full trailing year says cheap power is decisively better, and this machine has spent all 835 days in the UAE.

The average is not the price to plan on. Today's cost per coin is.

The tally, and what is left in it

In 835 days it has mined and kept 0.1498 BTC, worth $12,501 today, for $6,970 of electricity. That is $5,530 of cashflow, or 68% of its $8,192 landed cost, a little over half way through a four-year life.

At today's difficulty and with bitcoin back at its previous high of $124,493, it has another 0.090 BTC in it before the April 2028 halving, worth about $11,208. That is roughly $6,466 of net after power, which on top of what it has banked takes it past its landed cost by then, and it is still running at the end of it.

What it means for a miner

The lesson is not that 16 J/TH is enough for ever. It is that the machine you buy has to clear its power at the bottom of the market, not the average of it, and the S21 Hyd did that with room for one more difficulty step. For the next low the margin has to come from efficiency.

The output of this machine has not changed in two years and three months. What has changed is the entry price: the last price we recorded for one, $2,146 on 5 June 2026, is the best entry it has ever had. A newer hydro generation makes a coin for far less electricity, and the S21+ Hyd and the S23 Hyd are where to look first.

The machines that make a coin for less than this one does today.

Sources and further reading

Which machines this covers

Disclosure

Firsthand Bitcoin sells and hosts mining hardware, including this machine. No manufacturer, distributor or affiliate programme paid for or reviewed this page and we take no commission on the links above. Historical figures are computed from daily bitcoin price and network hashprice, each day valued at its own prices. Nothing here is investment advice.