Green data center: the 2026 European ranking of the most virtuous operators

2026 methodology

Four weighted criteria: PUE (30%), hourly CFE (30%), % renewable PPA signed (25%), WUE / litres of water per kWh IT (15%).

Top 10

| Rank | Operator | PUE | CFE | % renew. PPA | Score | |---|---|---|---|---|---| | 1 | Google (Hamina, Eemshaven) | 1.09 | 91% | 100% | 94/100 | | 2 | Microsoft (Dublin, Cardiff) | 1.12 | 89% | 100% | 91/100 | | 3 | Meta (Luleå, Odense) | 1.10 | 87% | 100% | 90/100 | | 4 | AWS (Stockholm, Aragón) | 1.15 | 84% | 100% | 87/100 | | 5 | Equinix (multi) | 1.32 | 78% | 96% | 81/100 | | 6 | Digital Realty | 1.38 | 72% | 88% | 75/100 | | 7 | Data4 | 1.30 | 70% | 85% | 74/100 | | 8 | OVH | 1.28 | 65% | 80% | 71/100 | | 9 | Iron Mountain | 1.42 | 68% | 92% | 70/100 | | 10 | Atos / Eviden | 1.45 | 62% | 78% | 65/100 |

2026 technical levers

• Nordic free cooling: PUE 1.05–1.12 all year
• Immersion liquid cooling: -40% cooling energy
• Heat reuse: district heating (Stockholm, Helsinki, Paris 13)
• AI workload shifting: geographic relocation based on real-time CFE

Voltarione and the CFE score

The Voltarione API exposes for each signed PPA: forecast hourly CFE, source generation curve and 8,760 h projection. Pluggable directly into CSRD/ESRS-E1 reporting.