The worked example: one S21 Hydro
The machine is an Antminer S21 Hydro, rated at 5.36 kW. Running all year it uses 5.36 kW × 8,760 hours = 46,954 kWh.
| Option | Rate | Paid when | Power for one year | Power for seven years |
|---|---|---|---|---|
| Pay as you go (Segments Hosting) | 6.0¢/kWh | Monthly, on the kWh actually used | $2,817 | $19,721 at an unchanged rate |
| Seven years prepaid (a published Dubai offer) | 4.2¢/kWh | All of it upfront | not sold by the year | **$13,804 on day one** |
The prepayment saves $5,916 over seven years, but only if the machine runs every hour of all seven years. And it is paid in full before the first block is mined.
When the prepayment pays off
Divide the prepayment by what pay-as-you-go costs each year: $13,804 ÷ $2,817 = 4.9 years. At the 95% uptime most hosts target it is 5.2 years. Our hosting agreement lets the rate rise by at most 10% a year after the first 12 months. Even if it rose by that much every year, the prepayment would take about 4.2 years to pay off.
- Retire the machine after three years and you have paid about $7,888 for power it never used.
- Retire it after four years and the unused power is about $5,916. That is the whole saving, spent on a machine that is already switched off.
Ask whether unused prepaid power is refunded, credited to another machine or lost. If the contract does not say, assume it is lost.
Four things a seven-year prepayment ties you to
1. The 2028 halving
Around April 2028 the block reward halves, and so does the bitcoin each terahash earns. A machine that pays well today can earn close to its power cost afterwards. With prepaid power you can no longer save money by switching it off. See what the 2028 halving means for a miner you buy today.
2. The machine’s working life
Seven years is longer than most owners plan to run one model. More efficient machines arrive every year, and many owners upgrade long before year seven.
3. Downtime you have already paid for
Metered hosting bills the kWh the machine actually used, so a machine that is off costs nothing. With prepaid power, ask what happens to the hours lost to a repair, a hall outage or a curtailment.
4. The host itself
A prepayment is only as safe as the company holding it. Check which company signs the contract, where it is licensed, and what happens to your money if it closes or moves your machine.
Ask these before you prepay
- Is the prepaid rate only for miners bought from you? What is the rate for a machine I bring?
- Is unused prepaid power refunded or credited if I retire, sell or move the machine?
- Are hours lost to repairs or outages credited, and how are they measured?
- Which licensed company holds my money, and in which country?
- Can I see the site, and my miner’s worker in the pool, before the money is gone?
For the rates each UAE host publishes, prepaid offers included, see UAE hosting companies compared.
How Segments bills
- Hosting at 6.0¢/kWh, billed monthly on the kWh actually used. The minimum term is 12 months, then month to month. Leaving in the first 12 months costs $300 per machine.
- Full-care hosting at 6.8¢/kWh for 24 months, with no repair charges under a Segments warranty.
- One-off setup, shipping at $30/kW, and a refundable deposit of 30 days’ hosting, applied to your final bill.
- No hosting fee while a machine is in repair.
- No multi-year prepayment of power.
- Live status for every centre on the status page, and you can visit a centre before you buy.
Questions
- Is prepaid hosting ever worth it?
- It can be, if you are confident the machine will run at full power for longer than the break-even (about five years in our example) and the contract refunds or transfers unused power.
- Why not just compare the rate per kWh?
- Because the rate hides when you pay. 4.2¢ paid seven years upfront and 6.0¢ paid monthly need very different amounts of cash on day one, and leave you with very different risks.
- Does Segments offer a prepaid discount?
- No. Hosting is 6.0¢ per kWh, billed monthly on the power actually used, with a 12-month minimum term.