Inside the RZO Gais Data Centre

How environmentally sustainable is the energy source powering your data centre?

Sustainability starts with energy. 100% of the electricity required to operate the RZO data centre comes from renewable Swiss sources. A significant portion is generated directly on site: the roof and facade of the building form an active solar system, producing around 230,000 kWh annually. This local generation not only reduces dependency on external supply but also reinforces RZO’s commitment to environmentally responsible operations.

The DACH region has only two Tier IV data centres, and yours is one of them. Why was this level chosen?

When RZO entered the colocation market, the goal was clear: not to be just another data centre, but to set new standards. Achieving the Uptime Institute Tier IV Facility Certification (TCCF) – the most demanding certification in the industry – was a deliberate decision that reflects these ambitions.

Tier IV means that all critical infrastructure – power, cooling, and data lines – is fully redundant and physically separated into different fire compartments. This design enables a calculated availability of 99.998%. Combined with preventive maintenance, comprehensive business continuity management (BCM) plans, and a professional operations team, this results in continuous, uninterrupted operation.

How do you ensure uninterrupted power supply, even during outages?

Although the local power substation in Gais has existed for “only” 45 years, there has not been a single power outage during this entire period. The reason lies in its exceptional connectivity: the substation is supplied by five power lines from three different directions, making it one of the most reliable substations in Eastern Switzerland.

In addition to this, RZO operates diesel generators for emergency scenarios. On-site fuel reserves are sufficient to maintain full operations for at least 72 hours without refuelling. An equivalent fuel quantity is also stored at the supplier’s location, with guaranteed delivery within 24 hours if required.

What makes the data centre exceptionally secure?

It is important to distinguish between availability and security. While availability focuses on power and cooling, security refers to physical access protection.

Absolute security does not exist – but RZO has implemented an exceptionally high level of physical protection. For understandable security reasons, not all measures can be disclosed, but they include biometric access control, comprehensive video surveillance, bulletproof windows, and laser-based roof monitoring, among others.

The facility is often compared to a prison – although the intention is the opposite. The goal is not to prevent escape, but to prevent unauthorised access altogether.

How do you integrate sustainability into daily operations including waste heat reuse?

Many believe that ecology and economics cannot coexist. RZO proves otherwise.

Conventional data centres typically require around 60% additional energy for cooling and uninterruptible power systems. Thanks to its location at 920 metres above sea level and a highly sophisticated cooling design, RZO can cool servers year-round without compressors. Additionally, the data centre uses flywheel-based UPS systems instead of batteries, which significantly reduces energy consumption.

As a result, RZO requires only around 15% additional energy, instead of the usual 60%.

Beyond efficiency, RZO has implemented a circular energy model: excess heat from the data centre is supplied to a neighbouring mountain cheese dairy. This enables the production of approximately 1,800 tons of cheese per year, while reducing CO₂ emissions by around 200 tons annually. At the same time, the reuse of waste heat further reduces RZO’s own cooling requirements – a clear win-win situation.

Who built the data centre, why Gais, and why would energy companies invest in such a project?

The project was initiated in 2016 by St. Gallisch-Appenzellische Kraftwerke AG (SAK) and completed in 2018. I led the project as project manager from the planning phase through to completion. During the construction phase, the City of St. Gallen acquired a 20% stake, reinforcing the project’s regional and strategic importance.

This ownership structure reflects a broader logic. Energy companies are natural investors in data centres: they already operate extensive fibre-to-the-home (FTTH) networks, deliver digital services, and are accustomed to planning, financing, and operating critical infrastructure designed to perform reliably over decades.

This long-term infrastructure-focused mindset directly influenced the choice of location. Gais, situated at 920 metres above sea level, benefits from average air temperatures around 5°C lower than in cities such as Zurich. Every degree that does not need to be actively cooled increases energy efficiency by approximately 6%, creating a decisive advantage for sustainable, long-term data centre operations.

What this means for HORISEN and its customers

The RZO Gais Data Centre is more than a hosting facility – it is a carefully engineered ecosystem where reliability, security, and sustainability are deeply interconnected. From Tier IV-certified redundancy and exceptional power resilience to innovative cooling and circular energy reuse, RZO sets a benchmark for future-ready digital infrastructure.

For HORISEN and its customers, this means confidence, transparency, and long-term stability – backed by infrastructure designed to operate without compromise, today and for decades to come.