Two questions are being asked on opposite sides of the same forum. Miners ask: is solar mining actually worth it? And solar owners ask why a large, expensive system is saving so much less than the salesman promised. Those two questions have one answer, and it is more interesting than either group expects.
- ✓Solar and mining do not fit together naturally. The sun is variable and mining wants a constant load.
- ✓The real opportunity is not free power. It is surplus — electricity you generate but are paid very little for exporting.
- ✓At today’s Bitcoin price, an efficient miner turns one kilowatt-hour into more value than most export tariffs pay for it.
- ✓But a miner running only in daylight works roughly a fifth of the hours, so the machine takes far longer to pay for itself.
- ✓Solar plus mining is a way to make surplus useful. It is not a way to mine for nothing.
The disappointment nobody talks about
A post this month described an 8.2 kW rooftop system, fourteen months in, saving around seventy-five a month against a build cost in the tens of thousands. The owner was not complaining about the hardware. It works. The panels produce. The disappointment was the gap between what was produced and what it was worth.
That gap has one cause, and it is the single most important thing in this article.
A kilowatt-hour you use yourself saves you the full retail price of electricity. A kilowatt-hour you export earns you whatever the export tariff is, which is usually a fraction of that. Most home solar systems produce their surplus at exactly the times nobody is home to use it.
Why solar and mining fight each other
Solar output is a hill. It starts at nothing, rises to a peak around midday, and falls back to nothing. A Bitcoin miner is a flat line. It wants the same power at 3am as at midday, every day, forever.
What a kilowatt-hour is actually worth
This is where it becomes interesting. Ask what one surplus kilowatt-hour is worth, depending on what you do with it.
For a miner, the answer comes straight from efficiency. A machine at 9.5 J/TH produces about $0.1762 of Bitcoin for every kilowatt-hour you feed it, at today’s price and difficulty. That is its break-even rate, viewed from the other direction.
So the answer to "is solar mining worth it?" is: worth it compared with what? Compared with exporting surplus at a poor tariff, an efficient miner is clearly better. Compared with using that electricity in your own home instead of buying it, it is worse. Mine the genuine surplus, not the electricity you could have used.
The duty-cycle problem
Here is the catch that ruins a lot of spreadsheets. Value-per-kilowatt-hour is only half the story. The other half is how many hours the machine actually runs.
A miner on the grid runs about 8,760 hours a year. A miner running only on direct solar surplus might run 1,200 to 1,800. The machine costs the same either way.
Batteries, miners, or both?
If you have surplus and you want to do something useful with it, there are three realistic options. They are not mutually exclusive.
| Option | What it does with surplus | Strength | Weakness |
|---|---|---|---|
| Export to the grid | Sells it at the export tariff. | Zero cost, zero effort, zero maintenance. | Usually the lowest value per kilowatt-hour available. |
| Battery storage | Stores it for your own evening use. | Displaces electricity at full retail price — the highest value per unit. | High cost per kilowatt-hour of capacity, and it degrades over time. |
| Hot water or heating | Turns surplus into stored heat. | Very cheap to fit, genuinely useful, no moving parts. | Only helpful when you actually need heat, and capacity is limited. |
| Bitcoin miner | Converts surplus into Bitcoin. | Higher value per unit than most export tariffs. Fully controllable, switch on and off instantly. | Hardware sits idle most hours, plus noise and heat to manage. |
A miner is one of the very few loads you can switch on and off instantly with no penalty. That makes it an excellent dump load — the thing that soaks up whatever is left after the house and the battery have taken what they need. Used that way, it does not compete with your other options. It picks up what they leave behind.
When solar mining genuinely works
It works well in four specific situations, and poorly outside them.
- ✓You already have solar, and a poor export tariff. The panels are a sunk cost. Anything that beats the export rate is a genuine gain.
- ✓You have surplus you currently curtail. Some systems switch off in the middle of the day because there is nowhere for the power to go. That electricity is worth exactly nothing right now.
- ✓You are in a sunny climate with long, consistent days. Duty cycle is everything, and consistency matters more than peak output.
- ✓You use the heat. If the miner's heat displaces heating you would have paid for, the economics change substantially in its favour.
And it works poorly when:
- You are buying panels specifically in order to mine. Industrial power is cheaper per kilowatt-hour than domestic solar, once you count the capital.
- Your export tariff is generous. If you are paid well to export, exporting is simpler.
- You have a short, cloudy season and a long dark winter. The duty cycle collapses.
- You need predictable output. Weather is not predictable, and neither is your production.
That last point is the honest boundary. Solar mining is a good way to squeeze value from surplus you already have. It is not a route to low-cost mining at scale — for that, the comparison is industrial power on a fixed contract. Across the OneMiners hosting network the average is $0.0480 per kWh on seven-year fixed rates across 20 sites, with the machine running 98%+ of the time rather than a fifth of it. The hours are the difference, more than the rate.
Efficiency decides what your surplus is worth
Compare what an efficient miner does with a kilowatt-hour against what a fixed industrial rate does with the same machine, all year round.
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Where these numbers come from
- Value-per-kWh figures are derived from live catalogue wattage and hash rate at a Bitcoin price of $79,264 and network hash rate 887.8 EH/s (mempool.space and CoinGecko, 27 August 2026).
- Export tariff and retail price bands are illustrative ranges; check your own tariff, which is the only one that matters.
- Solar generation curve is a modelled clear-summer-day profile for an 8 kW residential array, used for shape rather than exact output.
- Duty-cycle percentages are planning estimates, not measured site data.
This article is for information and education only. It is not financial advice. Mining results change with the Bitcoin price, network difficulty, your electricity rate and your hardware. Numbers shown are examples from public data on the date of writing, not a promise of any result. Always do your own research.
