Battery energy storage systems replace diesel: A new era for Microsoft's data centers

Microsoft’s next‑generation data center in Stackbo, Sweden, has taken a bold step toward sustainability by integrating Saft’s MW‑scale Li‑ion Battery Energy Storage Systems (BESS) to replace traditional diesel backup generators. This milestone demonstrates how battery‑powered microgrids can deliver reliable, resilient, and low‑carbon backup power for large‑scale digital infrastructures.

At the heart of the solution is a grid‑forming microgrid equipped with full blackstart capability. This allows the data center to restart autonomously from a complete shutdown and operate instantly and independently for up to 80 minutes, even under demanding environmental conditions. The system’s capacity can be scaled to provide longer autonomy when required, offering flexibility for future energy needs.

This battery‑based architecture showcases a transformative model for data center power supply. It not only eliminates diesel emissions but also unlocks new pathways for integrating clean energy and optimizing grid interaction. Among its core benefits:

• Replacing diesel backup generators, significantly lowering operational carbon footprints
• Enabling the use of locally generated renewable energy, such as wind or solar
• Storing clean electricity purchased through PPAs, especially during periods of high renewable production
• Supporting “shared grid connection” models by reducing or offsetting grid power during peak demand
• Creating new value streams, including participation in grid ancillary services or demand‑response programs

As data centers continue to expand globally, solutions like Saft’s BESS demonstrate how energy reliability and sustainability can go hand‑in‑hand, paving the way for cleaner, smarter digital infrastructure.