Why spend so much to change businesses? And what does the decision mean for owners who intend to keep running their S21s?
All miners at the site were shut down on September 1, according to Hyperscale's September 2 announcement. It has a 20 MW agreement with a California-based cloud provider. The announcement did not say that the customer's servers were running yet.
For the site owner, the building, grid connection and staff offer other possibilities. A customer with different equipment may want to use the same premises. Getting those premises ready, however, takes money and time.
The cost of converting a mine
Hyperscale had put a number on that work in June. It estimated that preparing around 60,000 square feet, roughly 5,600 square metres, for the initial 20 MW of AI capacity would cost $100 million to $120 million. That was a forecast in the June 24 project announcement, rather than a final bill for completed work.
An existing site still needs to accommodate the customer's servers, power, cooling and connectivity. Some infrastructure may be reusable; some will need replacing. Each site needs its own assessment and budget.
The timing matters, too. Mining has stopped while preparations for the next use continue. A construction delay can extend the period when the operator is paying expenses without providing the new service.
To judge the business case, you would need the contract terms, conversion costs and payment schedule. An announcement that a company is entering AI leaves much of that story untold.
Where the mining equipment goes
An ordinary air-cooled Antminer S21 cannot be switched over to training neural networks. Its chips are designed for SHA-256, the algorithm used in Bitcoin mining. They perform that particular job extremely quickly. New firmware cannot give them the capabilities of a GPU. BITMAIN's S21 documentation
For a sense of the architectural difference, consider NVIDIA's DGX GB200 NVL72 rack. It contains 72 GPUs connected through NVLink. The CPUs and GPUs are liquid-cooled, while some other components use air cooling. NVIDIA's hardware guide
AI systems vary, but that example helps explain why accommodating a new customer can require substantial work inside an existing building.
The miners can potentially be moved to another site, provided the economics work. The vacated building may be converted for a different customer. Those are separate decisions, with separate costs.
Hyperscale's September release does not identify the models it was using. The S21 on our cover illustrates the subject; it is not a record of equipment at the Michigan site.
A connected substation still leaves work to do
Another September announcement shows how long construction can take. IREN said on September 8 that its Sweetwater 1 substation had been energized earlier in 2026. The data centers under construction, with 300 MW of total power capacity, were targeted for delivery in the fourth quarter of 2027. IREN's announcement
A grid connection alone does not tell you when servers will be running or earning revenue.
Approvals also need careful reading. On September 9, Texas grid operator ERCOT announced document verification for projects conditionally included in Batch Zero. Participation depends on successfully completing that review. ERCOT's notice
Conditional inclusion, an energized substation and an operating facility describe different stages. For the company funding construction, the remaining work affects both the budget and the date it can serve a customer.
Mining continues elsewhere
One closure tells us little about the whole industry. In its September update, CleanSpark discussed infrastructure plans while also reporting 593 BTC mined during August. The production figures were unaudited. CleanSpark's September 8 update
A company with several sites can prepare one for a future customer while continuing to mine at another. The decision depends on each site's costs and available options.
Owners of smaller fleets have a different calculation. Owning S21s does not bring with it a building suitable for AI servers or a contract with a cloud provider. Any proposed new business needs its own budget, including the cost of getting started.
What to check at your own mine
For someone running a few S21s, a useful question is how long the current hosting terms will remain available.
Ask how long the electricity rate is fixed, when it can be revised, and what the contract says about disconnection and equipment removal. These questions become particularly relevant if the hosting provider is discussing AI plans. Check what the monthly charge includes, too: power, maintenance, space or a combination. A quoted price per kilowatt-hour may cover only part of the bill.
A simple example shows the scale. The 200 TH/s S21 has a specified power consumption of 3.5 kW at an inlet air temperature of 25°C. Suppose it draws that power continuously for 24 hours. It would use 84 kWh.
A one-cent increase in the energy price would add $0.84 a day, or $25.20 over 30 days. Across 100 machines, that would be $2,520 for the month.
The calculation covers only the difference in the machines' energy cost. It excludes premises overhead, separate hosting fees, taxes and downtime. Actual consumption needs measuring. It is an illustration, not a forecast that AI will raise your rate or a projection of mining returns.
That potential difference is worth understanding before renewing a hosting agreement or buying more equipment.
If you are keeping your S21s
You may have little room to negotiate the electricity rate. The way you run your miner is something you can review.
VNISH firmware, available through ROI ASIC, offers power presets and per-chip autotuning. These allow you to tune an S21 for your electricity rate and cooling conditions. That can improve mining economics without buying new hardware, but the benefit needs to be measured on your own machine. Firmware features at ROI ASIC
With expensive electricity, reducing consumption may pay better than chasing more hashrate, even if output falls a little. The energy savings need to outweigh lost revenue and additional fees. Cheaper power may lead to a different choice.
Compare readings from a separate electricity meter with actual pool results over comparable periods, accounting for firmware and pool fees. Check temperatures, errors and downtime as well: an unstable setting can erase the expected gain. Before installation, confirm compatibility with the particular device and review the manufacturer's warranty terms.
Want to work through the options for your S21? Contact ROI ASIC with the model, control board, current hashrate and power draw, and your electricity rate. Those details provide a useful starting point for discussing firmware and a single-device test.
ROI ASIC Research. Checked September 17, 2026. The AI-generated cover is an illustration, not a photograph of Hyperscale Data's site or an S21 installation guide. This article is not investment advice.