From MVA to miners: how many machines a site can power

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MVA, kVA and kW in plain terms

A grid connection and the transformer behind it are rated in kVA or MVA (1 MVA is 1,000 kVA). That is apparent power: the voltage times the current the equipment can carry. What a miner actually turns into hashing and heat is real power, measured in kW, and it is what the meter counts in kWh.

The link between the two is the power factor: kW = kVA × power factor. A load with a power factor of 1 uses every kVA as real power; at 0.9, a 1,000 kVA transformer is fully loaded at 900 kW. Modern ASIC power supplies correct their power factor and run close to 1 at full load, but pump and fan motors and other site loads pull it down, so no site is sized as if every kVA were a kW.

• kW: the real power a machine draws. An S21-class air-cooled miner draws about 3.5 kW.
• kWh: energy over time, and what hosting is billed on. 3.5 kW for 24 hours is 84 kWh.
• kVA and MVA: what the transformer and the grid connection can carry.
• MW: 1,000 kW of real power. Investors tend to talk in MW; grid connections and transformers are usually quoted in MVA.

Why only about 85% goes to miners

A site’s MVA is the ceiling for everything on it, not only the miners. Segments plans with a simple rule: power for miners = MVA × 85%. The other 15% or so covers:

• Cooling. On a hydro site, the pumps that move coolant and the fans on the cooling towers. On an air site, the exhaust fans and any evaporative cooling.
• Transformer and cable losses. Some power turns into heat between the grid and the rack.
• Power factor. The gap between kVA and kW described above.
• Site services. Lighting, network, cameras, the control room and offices.
• Headroom. Transformers run hotter in a Gulf summer, and running them at their limit around the clock shortens their life. A margin also absorbs miners that draw a little above their rated figure.

The 85% figure is a planning rule, not an engineering result. Each site’s real figure comes from its electrical design and cooling study, and it can come out a little higher or lower.

How many miners per MVA

The table applies the 85% rule and divides by the approximate draw per miner: about 5.5 kW for a hydro miner and about 3.5 kW for an S21-class air-cooled miner. Counts are rounded down, because you cannot run part of a machine.

For a 20 MVA plan, double the last row: 17,000 kW, about 3,090 hydro or 4,857 air miners. Both columns use the same 85% rule so they compare like for like; in practice hydro and air sites spend their overhead differently.

Miner count is not the real measure of a site. Hashrate per MW depends on efficiency: every 1,000 kW of miners at 15 J/TH gives about 66,700 TH/s, and at 20 J/TH about 50,000 TH/s. A hydro site holds fewer, larger machines, but hydro models are often the more efficient ones, and water cooling keeps them at full speed through the summer. See hydro, air or immersion cooling in Gulf heat.

Containers: what fits on a 6 MVA site

Many hydro sites are built from containers rather than halls. Bitmain publishes these figures for its Antspace HW5: a 40 ft container holding 210 miners and drawing 1,062 kW, paired with a dry-wet cooling tower rated at 1,200 kW, a little above the container’s own load.

On a 6 MVA site with 5,100 kW for miners, 5,100 ÷ 1,062 ≈ 4.8. That is four full containers (840 miners, 4,248 kW) with about 850 kW to spare, which could take part of a fifth container or other hydro racks.

Why 840 and not 927? The 927 figure fills all 5,100 kW with 5.5 kW miners; containers come in whole units of 210 machines. And power is only the first check. Containers need room for their cooling towers, pipework, clearances and access for cranes and trucks, and each one needs its own feed from the switchgear. A plot with the power for five containers may only fit four.

Container count = power for miners ÷ container load, rounded down, then checked against the plot layout and the cooling plan.

What the new UAE hydro sites mean

Segments has two new water-cooled sites in the UAE: a 6 MVA site that is energised, and a 4.5 MVA site awaiting its final inspection and energising. By the 85% rule they give about 5,100 kW and 3,825 kW for miners: room for roughly 927 and 695 hydro miners, about 1,620 together.

For buyers of hydro models, that means more water-cooled capacity in the UAE; ask for current availability on the hosting page. For investors planning their own 1 to 20 MW, the same arithmetic works on any plot: start from the MVA you can get, take 85%, and divide by the draw of the miner you plan to run.

What limits a site besides power

• Distance to the substation. Power on paper means nothing until a line reaches your transformer. The further the plot is from the substation, the more the cable and trenching cost, which is why Segments prices every build per project, by its land and its distance from the substation, rather than per MW.
• Cooling water. Hydro miners reject their heat into water, and dry-wet towers use water when they run wet in the hottest months. A hydro site needs a reliable supply.
• Approvals. Land use, the utility connection and safety permits all have to be in place before a miner switches on. The 4.5 MVA site above is an example: built, and waiting for its final inspection.
• Land and layout. Space for halls or containers, cooling, roads and later extension.
• Heat and dust. Gulf summer air passes 45 °C. Air sites need airflow and filtering sized for it; hydro sites need towers sized for the hottest week.

Segments has been building in the UAE for five years and delivers turnkey sites to order: land on lease or purchase, approvals, electrical infrastructure, and air, hydro or immersion halls, in 90 to 120 days of build time. See datacenter construction, or the miners we sell to match a model to a site.