Denmark will unveil Magne, Europe’s first large‑scale quantum computer, later this year. Built by Microsoft and Atom Computing, the machine sits on a €80m investment from the Novo Nordisk Foundation and EIFO. The project signals a milestone for European tech, but it also raises questions about the infrastructure needed to run thousands of qubits.

Quantum systems demand power rivaling today’s data centres. A 4,000‑qubit benchmark for commercial use pushes superconducting, photonic and ion‑trap designs to roughly 160, 100 and 140 MW respectively—comparable to a single hyperscale AI facility. Even photonic arrays can span thousands of square metres, with PsiQuantum’s Brisbane warehouse covering 540k sq. ft.

Quantum Motion counters with silicon spin qubits, fabricated on 300 mm CMOS lines that also make laptops. Their target system fits in five server racks and draws under 200 kW—about a thousand times less than other modalities at the same logical scale. Recent 1,024‑device cryo‑CMOS tests and >99 % fidelity cells suggest the engineering hurdles are surmountable.

As AI pushes data‑centre power toward 106 GW by 2035, quantum’s energy footprint must be scrutinised now. Europe’s pride in Magne should be matched by a realistic plan for scaling silicon‑based machines that fit existing grids. Ignoring these realities risks overloading power supplies when quantum becomes commercially viable.