A recent study conducted by two scientists from the University of Kent’s School of Computing in the UK compared the energy consumption rates of current ASIC-based miners and proposed quantum-based solutions. The team’s preprint research paper reveals that quantum computing systems demonstrated significantly better energy efficiency:
“We show that the transition to quantum-based mining could incur an energy saving by relatively conservative estimates of roughly 126.7 TWH, which is the equivalent of Sweden’s total energy consumption in 2020.”
As of May 2022, Bitcoin mining operations alone consumed over 150 terawatt hours per year, putting in perspective the potential impact of proposed quantum-based systems. The researchers performed experiments comparing three different quantum mining systems to an Antminer S19 XP ASIC miner. The quantum mining devices varied between a system with a single layer of fault tolerance, one with two layers of fault tolerance, and one without any error-correction features.
The paper notes that error correction is not a crucial factor in blockchain mining as compared to other quantum functions, where errors create noise that hinders a computing system’s computing accuracy. The researchers also point out that a classical Bitcoin miner is profitable with only a success-rate of about 0.000070%. Quantum-based systems can be adjusted over time for enhanced accuracy and efficiency, a feature lacking in classical systems.
The researchers also suggest that it should be possible to build miners using existing quantum technologies that can prove quantum advantage over classical computers, even though quantum computing technology is still in its infancy. A quantum miner does not necessarily have to be a universal, scalable quantum computer, and need only perform a single task. However, the researchers focused on a type of quantum computing system named a “noisy intermediate-scale quantum” (NISQ) system, which operates with about 50-100 qubits. The energy savings are theoretically feasible, but the costs of constructing and maintaining a quantum computing system in the 512 qubit range have historically been prohibitive for most firms.
Only IBM and D-Wave offer client-facing quantum computing systems in the same range, with D-Wave’s D2 being a 512-qubit processor and IBM’s Osprey having 433 qubits. However, their architectures differ so greatly that comparisons of their qubit counts are pointless.