Solar Panels for Data Centres in London

Serving London and the wider Greater London area, including Canary Wharf, Isle of Dogs, Stratford.

London data centres and the case for on-site solar PV

London hosts one of the world’s most important data centre clusters, with the Docklands area — specifically the Isle of Dogs, Harbour Exchange, and Coriander Avenue — forming the densest concentration of carrier-neutral colocation capacity in the UK. Telehouse has operated in Docklands since 1990; Equinix’s LD1–LD4 campus at Harbour Exchange handles more cross-connect traffic than any other UK data centre facility. Interxion, CenturyLink, Virtus, and Colt all operate significant facilities within walking distance of Canary Wharf.

This cluster serves as the primary UK point of interconnection for transatlantic cable systems, the London Internet Exchange (LINX), and most of the major financial services networks operating in the City and Canary Wharf. The buildings have exceptionally high power density — some Telehouse halls operate at 8–12 kW per rack — and the electrical infrastructure is some of the most mature in the world, with primary 33 kV supplies from UK Power Networks and extensive on-site standby generation.

For the purposes of solar PV, London data centres present a specific challenge: roof area is limited relative to IT load. A 10 MW data centre campus consuming 87 GWh per year cannot put a meaningful percentage of that on its own roof. But the economics still work strongly, for two reasons.

First, even 5–10% on-site generation contributes directly to the evidence pack that hyperscale tenants require for hourly CFE matching. A 500 kW system generating 440,000 kWh per year covers a real and auditable share of the load — more importantly, it covers the daytime hours when hourly CFE matching is easiest and when grid carbon intensity is lowest, making on-site generation disproportionately valuable for CFE reporting.

Second, London’s electricity grid rates are among the highest in the UK for large I&C customers, with half-hourly settled contracts typically running 24–30p/kWh all-in for the capacity, distribution, and energy elements. At those rates, a 500 kW rooftop system generates £100,000–£130,000 of annual cost avoidance — a compelling standalone business case even without the sustainability narrative.

The Docklands data centre cluster — what distinguishes it

The Docklands cluster operates at a different scale and specification to the rest of the UK data centre market. Key characteristics:

Primary grid supply: Most Docklands data centres have dedicated 33 kV or 11 kV primary supplies from UK Power Networks, fed from Hays Wharf or East Greenwich primary substations. These are diverse-fed where possible and have been upgraded multiple times since the early 2000s. New solar installations connect to the low-voltage secondary side and are fully behind-the-meter, with no interaction with the primary grid supply.

Standby generation: Most buildings have N+1 or 2N diesel standby generation, with some sites operating gas turbine or HVO-fuelled systems. Solar inverter design must account for generator islanding protection and anti-islanding certification (IEC 62116 / EN 50549). We specify inverters with certified generator-compatible anti-islanding across all London DC projects.

Floor loading constraints: Many of the original Docklands data centre buildings (converted 1980s–90s commercial buildings) have structural floor loading limits that affect plant room rooftop placement. PV arrays on older buildings may require structural engineering certification; we include a preliminary structural desk study in every feasibility.

Fire strategy: London Bridge fire regulations and Building Regulations Approved Document B apply to all rooftop works. PV arrays must be designed with 3m fire service access routes around the perimeter. We work to BS 8519 guidance on solar PV in high-rise and high-density occupancy buildings on all London projects.

City of London and EC postcode data centres

Beyond Docklands, the City of London (EC1–EC4) and adjacent areas host significant financial services data infrastructure, often in converted office buildings or purpose-built data suites beneath commercial towers. These facilities have different characteristics: smaller roof areas (often 200–800 sqm), more restrictive planning environments (City Corporation planning authority), and higher build costs per kW due to access constraints and high-value tenant environments.

For these facilities, PV systems of 50–200 kW are typically achievable and deliver strong economics because City grid rates are among the highest in the UK. We have experience working within the City Corporation’s conservation and planning framework, and have delivered rooftop solar to buildings adjacent to Grade I listed structures by providing pre-application heritage assessments.

UK Power Networks and London grid connection

UK Power Networks is the DNO for Greater London, East and South East England. For London data centres:

• Systems below 50 kW: G98 notification only (standard self-certification)
• Systems 50 kW–1 MW: G99 application, technical study required, 65 working-day statutory timescale
• Systems above 1 MW: G99 with extended study, typically 3–9 months

For fully self-consumed systems (zero-export design), the technical study is simplified because the DNO does not need to assess reverse power flow on the distribution network. We include zero-export relay specification on all London data centre systems above 100 kW, which typically reduces the G99 study timescale by 30–50%.

London-specific sustainability considerations

The Mayor of London’s London Environment Strategy (2018, updated 2022) sets a target for all new developments and major refurbishments to achieve net zero operational carbon. The strategy references on-site renewables as the preferred first measure, with offsetting only for residual emissions that cannot be addressed on-site. This is embedded in the London Plan 2021 Policy SI 2 (minimising greenhouse gas emissions), which applies to planning applications across all 33 London boroughs.

For data centre operators seeking planning permission for extensions, new halls, or major refurbishments, incorporation of on-site solar PV is increasingly required by planning officers as part of sustainability statements. We have provided technical feasibility reports for planning applications across Tower Hamlets, Greenwich, and the City of London on behalf of operators.

Frequently asked questions about London data centre solar

Does London get enough sun for rooftop solar to deliver a meaningful return? Yes. London receives 1,500–1,560 hours of sunshine per year — more than Manchester, Leeds, or Glasgow. A 500 kW London rooftop PV system typically generates 440,000–470,000 kWh per year. At 26p/kWh grid rate, that’s £114,000–£122,000 of annual cost avoidance. Even at the higher London build costs (£1,050–£1,250/kW for constrained Docklands access), payback runs 4.5–6 years.

Can we install PV on a live data centre in London without any downtime? Yes. We have delivered all London data centre solar projects with zero planned downtime. The design uses phased AC connection to limit the switchboard work to one panel section at a time, with a temporary bypass maintaining supply continuity throughout. Energisation is tested in each phase against the site’s UPS and generator transfer sequences.

Will the roof take the weight? Modern flat roofs (post-2000) in Docklands are typically rated at 0.5–1.5 kN/m² imposed load for plant access, which accommodates standard ballasted PV arrays at 0.15–0.25 kN/m². Older buildings require a structural survey, which we include in our feasibility process. Ground-mount is not usually available in London, so roof engineering is always a critical path item.

How does on-site solar PV interact with Telehouse’s and Equinix’s utility management? For hosted colocation customers, the operator controls the power infrastructure and the tenant pays for power as a service. On-site PV benefits the operator directly (reducing bought-in energy cost) and benefits the tenant indirectly through lower Scope 2 emissions attributable to their allocated space. We help operators structure the evidence pack so that tenant Scope 2 reporting accurately reflects the on-site generation share.

Get a feasibility study for your London data centre

We’ve delivered solar PV installations to data centres across the Docklands cluster, the City, and inner London. Every feasibility starts with a desk study — no site visit required initially. We sign NDA before engagement, provide PVSyst modelling, structural desk review, and Scope 2 evidence framework within 14 working days.