Hyperscaler Scope 2 requirements: on-site PV vs PPA matching
AWS, Microsoft Azure, Google Cloud, and Meta have all updated their supply chain sustainability programmes in 2024-2025 to distinguish on-site generation from PPA matching. Google Cloud's 24/7 Carbon-Free Energy goal requires hourly matching of consumption with local renewable generation — PPAs from remote solar farms only partially satisfy this requirement. On-site rooftop PV provides verifiable, co-located, hourly renewable generation that fully satisfies 24/7 CFE matching. AWS Scope 3 programme for colocation operators increasingly weights on-site generation above off-site PPA matching. Microsoft Azure (Cloud for Sustainability programme): on-site generation is weighted at 1.5× versus PPA matching in supplier sustainability scoring. We provide hyperscaler-format audit packs aligned with AWS, Azure, and Google Cloud programmes.
Data centre PV system design — UK specifics
Data centre rooftop PV requires specialist design: (1) Roof access planning — cooling towers, CRACs, CRAHs, AHUs, and DX units require maintenance clearance paths (LPC guidance: 1-2 metres clear around all plant). We map all plant before mounting design. (2) Structural loading — data centre roof structures are typically HEB or UB steel frames designed for heavy plant (cooling towers, chillers on plant decks). Ballasted PV adds 15-20 kg/sqm — compatible with post-2005 DC structural standards, confirmed via structural engineer. (3) LV electrical connection — solar PV connects to LV distribution board (below UPS). Does not interact with HV supply. Does not affect N+1 or N+2 UPS redundancy. (4) Export limitation — most UK data centres consuming 100% of on-site PV. G99 applications for systems above 1 MW include export limiting relay to 0 MW. (5) DCIM integration — solar generation data provided in standard SNMP, Modbus TCP, or REST API format for integration into DCIM (Data Centre Infrastructure Management) and BMS.
UK data centre solar by region and DNO
London arc (M25 — Slough, Woking, Guildford, Dartford, Hounslow): primary UK DC cluster — Google (Waltham Cross), Microsoft (Iver), Amazon AWS (West Drayton, Slough). SSEN (Hampshire/Berkshire) and UKPN (Kent/Essex). G99: 4-8 months. Manchester (Salford, Altrincham, Warrington): Ark Manchester, Equinix MA3, iDC. Electricity North West: 5-8 months G99. East Midlands (Corby, Northampton, Coventry): emerging market. WPD: 5-7 months. South Wales (Cardiff, Newport): TeleCity/Equinix, BT Openreach. WPD: 6-8 months. Scotland (Edinburgh Park, Strathclyde): Pulsant, Node4. SP Energy Networks: 8-12 months.
Common questions
Does on-site rooftop PV satisfy Google Cloud's 24/7 Carbon-Free Energy requirement?
Yes — on-site PV is the highest-quality renewable for 24/7 CFE purposes. It provides hourly, co-located, verifiable renewable generation that matches data centre consumption in real time (daytime hours). Night-time hours require either grid carbon intensity matching (UK grid is improving) or battery storage (adds cost). We design PV systems for 24/7 CFE reporting format and provide hourly generation data in CFE-compatible format.
How large a PV system can fit on a UK data centre roof?
Depends on roof area, plant layout, and structural loading. A 5,000 sqm net roof area (after plant clearances) typically accommodates 600-900 kW. A 20,000 sqm hyperscale DC roof can accommodate 2-4 MW. We survey and design to maximise achievable capacity within plant clearance and structural constraints.