UK data centres are the most energy-intensive commercial buildings in the country. IT load + cooling + UPS losses + lighting create a 24/7 baseload that absorbs essentially all rooftop solar generation regardless of weather. Combined with high grid retail tariffs and customer (cloud, SaaS, financial services) net zero pressure, solar PV on data centre roofs delivers exceptional economics — typical payback 4 years and IRR above 22%.
Why solar PV fits data centre solar
- 24/7 IT + cooling load = 92–96% self-consumption — highest in commercial solar
- Customer (cloud customer, SaaS tenant, financial services) net zero pressure intense
- PUE (Power Usage Effectiveness) reporting directly improves with on-site renewable share
- Tier III/IV redundancy preserved — solar is N+1 or 2N supplementary, not critical path
- ECCC (European Code of Conduct for Data Centres) alignment
- Customer audit pack: AWS, Azure, GCP, Salesforce, FTSE 100 financial services criteria
System design and sizing
Data centre solar sizing is unusual — the IT load typically exceeds achievable PV generation by 5–10x even on the largest rooftop systems. We size to maximise roof utilisation with high-efficiency modules (typically Mono PERC or N-type TOPCon at 21–22% module efficiency) given the 24/7 self-consumption guarantee. Battery storage is rarely economic for data centres because the load profile is so flat — instead, we pair PV with longer-term PPA contracts for the residual demand.
Electrical design must integrate carefully with the data centre's power distribution architecture. We work with the customer's critical engineering team to ensure PV connection respects N+1 or 2N redundancy requirements. Typically the PV connects to the non-critical building services switchboard and not the IT-critical bus.
Compliance and regulation
Tier III/IV uptime requirements preserved (PV is supplementary, not critical path). ECCC alignment. ISO/IEC 27001 information security (PV monitoring platform must be air-gapped from IT-critical networks). Customer audit packs aligned with AWS Climate Pledge, Azure Sustainability, GCP Carbon Sense, and major financial services net zero targets. Acoustic considerations (inverters near IT halls).
Recent install — 3.4 MW install on West London colo data centre
A West London colocation data centre operator hosting major cloud and financial services tenants. 60 MW IT capacity. Energy spend £42m/year. Tier III certified.
System
3.4 MW (6,250 panels)
Annual generation
3,150,000 kWh
Annual saving
£693,000
Payback
4.1 years
Self-consumption
96%
Outcome: Used in tenant audit packs (3 cloud customers, 2 financial services). Improved PUE from 1.42 to 1.36. Phase 2 across two further sites in commissioning.
Common questions about data centre solar
Will solar PV affect our Tier III/IV uptime certification?
No. PV is designed as N+1 or 2N supplementary supply, not critical path. The connection point is the non-critical building services switchboard, not the IT-critical bus. Uptime certification is preserved. We work with your critical engineering team and Uptime Institute consultants where applicable to confirm design before commissioning.
How does solar improve PUE?
PUE (Power Usage Effectiveness) measures total facility power divided by IT load. On-site renewable generation reduces the grid-supplied component of total facility power, mathematically improving PUE. A 3 MW install on a 60 MW data centre typically improves PUE by 0.05–0.08 — meaningful in customer audit comparisons.
What about the customer audit pack for cloud customers?
AWS Climate Pledge, Azure Sustainability, GCP Carbon Sense, and major SaaS and financial services customers all have specific verification documentation requirements. Our standard audit pack (PVSyst yield model, monthly generation export, embodied carbon LCA, MCS certificate) is supplemented with customer-specific verification certificates aligned to each major hyperscaler's programme.
Why is battery storage not always recommended for data centres?
Data centre load profile is unusually flat — IT load typically varies less than 10% across 24 hours. PV generation is daytime-only. Battery storage to shift solar generation to overnight is rarely economic because the marginal value of the shifted kWh is small relative to direct daytime self-consumption (which is already 95%+). Instead, we typically pair PV with longer-term PPA contracts for residual demand.
How do you handle inverter acoustic emissions near IT halls?
Modern string inverters typically emit 50–60 dB at 1m, comparable to office HVAC. We design inverter placement to maintain acoustic separation from IT halls and customer-occupied spaces. Where required, we use acoustic enclosures rated to 40 dB for sensitive areas. Acoustic survey is part of our standard structural and electrical survey deliverable.