Microsoft opens first Mount Pleasant data center, 550 staff on site

Microsoft announced that its first data center in Mount Pleasant, Wisconsin, is fully operational, bringing 550 full‑time staff online and positioning the state as the home of the “world’s most powerful supercomputer” for AI workloads【2】. The launch underscores Microsoft’s $4.7 billion hyperscale construction plan in Wisconsin through 2028 and signals a sizable increase in regional tech employment and electricity demand.

Facility rollout and local impact

The Fairwater campus went live after startup activities in April, with equipment already online and a second building under construction slated for completion in 2028【2】. Microsoft purchased 315 acres for $50 million in 2023 and has already paid $3.8 million in property taxes for 2025, without requiring additional public borrowing or new infrastructure【3】. The company’s hiring drive is expected to lift full‑time staff to about 800 when the second phase is finished, expanding the local high‑skill job pool.

Energy and competitive context

We Energies projects that Microsoft’s Mount Pleasant campus, together with its Vantage site in Port Washington, will add roughly 3.9 GW of electricity demand over the next five years, a 45 % rise in regional load【3】. This makes Fairwater the largest single electric load ever served by Wisconsin Electric, a scale that took the utility 125 years to achieve. While Microsoft touts the facility as the world’s most powerful supercomputer for AI training, the claim rests on AI‑training throughput rather than the LINPACK benchmark used by the TOP500 list, and it has not been independently verified【3】.

What to watch

• Completion of the second Mount Pleasant building and the resulting staff increase to ~800 (target 2028).
• Updates from We Energies on rate cases and whether new infrastructure costs will be passed to residential customers.
• Any third‑party benchmarking of Fairwater’s AI training performance that could confirm or challenge Microsoft’s supercomputer claim.

The opening of Fairwater marks a pivotal shift for Wisconsin’s tech landscape, turning the state into a hub for AI‑intensive workloads while raising questions about energy pricing, local hiring outcomes, and the veracity of the supercomputer claim.