How much energy does a quantum computer actually use?

Defining energy efficiency as algorithms executed per joule, this study surveys superconducting, silicon spin, trapped-ion, neutral-atom, and photonic qubit platforms with input from hardware experts. Each platform carries distinct energy trade-offs: some excel at fast gate speeds but demand heavy cryogenic or laser infrastructure, others are more frugal at the hardware level but slower. Beyond reporting current consumption figures, the work proposes a unified benchmarking framework applicable to future architectures — a prerequisite for any honest comparison between quantum and classical computation.