Bitcoin mining is like a lottery: miners sift through billions of numbers to find one lucky winner. A regular computer does this blindly, burning electricity. A quantum computer could sort through possibilities faster, like finding a needle in a haystack by shaking the whole stack at once.
The authors of a new study calculated what such a quantum "shaker" would actually cost. They accounted for everything: the qubits themselves, cooling systems, manufacturing plants, and logistics. The result is sobering. For the easiest task, finding an incomplete key, you'd need around 100 million qubits and 10 gigawatts of power. That's like ten large nuclear power plants.
But the real Bitcoin network is far more complex. To outpace all miners on the planet at current difficulty, a quantum computer would need 10 to the 23rd power qubits and 10 to the 25th power watts. That's comparable to the radiation of an entire star. Humanity today produces billions of times less.
Quantum mining turns out to be an economic absurdity. Even if engineers built a perfect quantum computer, the electricity bill would make mining unprofitable. Bitcoin will remain in the hands of conventional farms for the foreseeable future, and the quantum threat applies only to signatures, not mining.
as written by the authors arXiv:2603.25519
Bitcoin already faces a quantum threat through Shor attacks on elliptic-curve signatures. This paper isolates the other component that public discussion often conflates with it: mining. Grover's algorithm halves the exponent of brute-force search, promising a quadratic edge to any quantum miner of Bitcoin. Exactly how large that edge grows depends on fault-tolerant hardware. No prior study has costed that hardware end to end. We build an open-source estimator that sweeps the full attack surface: reversible oracles for double-SHA-256 mining and RIPEMD-based address preimages, surface-code factory sizing, fleet logistics under Nakamoto-consensus timing, and Kardashev-scale energy accounting. A parametric sweep over difficulty bits b, runtime caps, and target success probabilities reveals a sharp transition. At the most favourable partial-preimage setting (b = 32, 2^224 marked states), a superconducting surface-code fleet still requires about 10^8 physical qubits and about 10^4 MW. That load is comparable to a large national grid. Tightening to Bitcoin's January 2025 mainnet difficulty (b about 79) explodes the bill to about 10^23 qubits and about 10^25 W, approaching the Kardashev Type II threshold. These numbers settle a narrower question than "Is Bitcoin quantum-secure?" Once Grover mining is lifted from asymptotic query counts to fault-tolerant physical cost, practical quantum mining collapses under oracle, distillation, and fleet overhead. To push mining into non-trivial consensus effects, one must invoke astronomical quantum fleets operating at energy scales that lie far above present-day civilization.
For a quantum computer to outpace all Bitcoin miners, it would need more energy than Earth receives from the Sun in a year.
The idea of using stellar energy for computation evokes 'The Matrix', where machines enslaved humans for electricity.