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Progress report · Nov 4, 2026 · 4 min read

569 days in the UAE, the Antminer S21+ Hyd has never come within $6 of its power line

Bought in April 2025 and racked in the UAE, the 15 J/TH S21+ Hyd has paid its power bill every day since. Its line is $21.60 of hashprice at 6¢, the lowest hashprice since the 2024 halving was $27.74, and the one move left in its life is to Nigeria.

An Antminer S21+ Hyd water-cooled miner, the store photograph shown whole on the Firsthand card with the words Antminer S21+ Hyd, progress report, 15 J/TH, 395 TH/s hydro-cooled

Bitmain Antminer S21+ Hyd (395 TH/s)

Bought in April 2025 and racked in the UAE from the first day

A 395 TH/s S21+ Hyd at 15 J/TH, bought at $5,848 and landed at $7,240, racked in the UAE at 6¢ in April 2025. It is water-cooled, so its home is the UAE, where the water plant and the manufacturer’s warranty centre are, and it has been there for all 569 days. The store lists three smaller bins of the same machine, 319, 338 and 358 TH/s, at the same 15 J/TH; this report follows the 395 TH/s unit.

It has mined and kept 0.1052 BTC, worth about $8,068 today, for $5,233 of electricity. That is $2,836 of cashflow, or 39% of its landed cost, on a machine a little over a third of the way through a four-year life. Days spent switched off in that time: 0.

Chart: Coins kept since April 2025, the electricity that made them, and where the forward figures put it by the April 2028 halving.

Its line is $21.60, and hashprice has never come near it

A machine’s line is the hashprice at which it stops covering its own power. At 15 J/TH a petahash uses 360 kWh a day, which is $21.60 at 6¢ and $14.04 at Nigeria’s 3.9¢. Network hashprice was $32.70 per petahash per day on 3 November on our hashprice chart, so the UAE line is $11.10 under it and Nigeria’s is $18.66 under it.

The lowest it has been since the April 2024 halving was $27.74, on 6 June 2026. That is $6.14 above this machine’s 6¢ line, and on no day since the halving has hashprice fallen to it.

At 6¢ the machine makes a bitcoin for about $55,000 of electricity today, against a bitcoin price of $80,372. Over its run it has averaged about $49,700 a coin. At Nigeria’s 3.9¢, with that site’s lower uptime already counted, a coin costs about $35,800.

At 15 J/TH a petahash burns 360 kWh a day. That is $21.60 at 6¢ and $14.04 at Nigeria’s 3.9¢.

Chart: Network hashprice per petahash per day since the machine was bought. The S21+ Hyd needs about $22 of it at 6¢ and about $14 at 3.9¢. Open the chart

After the halving the cheaper power does the work

The April 2028 halving cuts the coins a petahash earns in half. At today’s price and difficulty that would put hashprice near $16.35. That is $5.25 under this machine’s 6¢ line and $2.31 over Nigeria’s. It is today’s conditions held flat, not a forecast, and it is why every projection we publish assumes the old high returns.

At 15 J/TH, about 4.5¢ is the highest power rate that still clears across the halving on those flat conditions, so this is a machine whose second half belongs on Nigeria’s power. It makes that crossing once, and the guide to the one-way move explains why it does not shuttle back.

On the assumption that bitcoin returns to its previous high of $124,493, it adds another 0.089 BTC by April 2028, worth about $11,100: roughly 1.9× its landed cost by the halving. The guide to efficiency and halvings shows where the line sits at every J/TH.

The entry price has settled where a buyer can use it

The first price we hold for the 395 TH/s unit, on 20 February 2025, was $18.69 a terahash. The entry price has settled since, and on 21 September 2026 it was $6.93 a terahash; its lowest was $6.83 on 15 July 2026. It is $6.93 today, $2,737 a unit, for the same 395 TH/s at the same 15 J/TH.

A low entry price does a lot of work. At today’s price this machine returns about 34% in its first year in the UAE and 40% in Nigeria, at today’s price and difficulty.

Chart: What the 395 TH/s unit has cost, from the first price we hold. The machine and its output are unchanged; only the entry price has moved.

Who should buy one, and who should look one step on

Buy it if you want a water-cooled machine a little over a year and a half into its life at a low entry price, you are racking in the UAE, and you are content for its second half to run on Nigeria’s power.

Look at the S21e XP Hyd instead if cost per coin is the aim: at $8.82 a terahash it returns about 39% in year one against this machine’s 34%, for a coin that costs about $47,800. The figure above ranks what beats this machine on cost per coin and then on first-year return, in stock today.

What beats it on cost per coin and on first-year return, in stock today.

Which machines this covers

The other side of this machine

The S21+ Hyd is the best-returning machine on our floor — 395 TH/s from one box at a settled entry price, and one of the strongest first-year returns we host. Seventeen months in, here is what it has banked and what is left in it.

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.