Integrating Sustainable Water Solutions into UK Data Centre Expansion: The Waterworks Model Executive Summary UK data centres lead in water efficiency: 51% use waterless cooling systems (air or refrigerants), 64% consume less than 10,000 m³ annually (comparable to a leisure centre), and only 4% exceed 100,000 m³ per year.[1][2] 89% measure usage or operate non-water-dependent systems.[1] The Waterworks Model builds on this foundation, integrating rainwater harvesting, closed-loop cooling hubs, AI-driven forecasting, and heat reuse to future-proof against AI-driven compute growth and projected water shortfalls (up to ~5 billion litres/day deficit by 2055 across England).[3][4] This ensures resilient, low-carbon digital infrastructure aligned with net-zero and national strategies, with strong economic returns via reduced OPEX and potential revenue streams. 1. UK Water & Data Centre Context A 2025 survey of 73 commercial data centre sites in England (collaborative with the Environment Agency) shows strong efficiency trends:[1][2] - 51% use waterless cooling. - 64% <10,000 m³/year. - 4% >100,000 m³/year (in line with industrial norms). - 89% measure or avoid water for cooling. These reflect proactive adoption amid rising AI demands. However, national planning highlights the need to integrate emerging digital needs into long-term water resilience, as current Water Resources Management Plans (finalised 2025) do not fully account for novel infrastructure like data centres.[3][4] 2. The Waterworks Model 2.1 Rainwater Capture & Storage Site-integrated systems harvest and pre-treat rainfall, reducing potable mains reliance in suitable regions. 2.2 Closed-Loop Cooling Hubs Minimize evaporation; enable heat recovery for district heating/agriculture—achieving 70–95% freshwater reductions vs. traditional evaporative in optimized designs.[1] 2.3 AI-Driven Smart Water Forecasting Predictive tools optimize cycles, balance seasonal demands, and coordinate with authorities for efficient allocation. 2.4 Heat Reuse & Circular Infrastructure Recover reject heat for community energy, cutting emissions and supporting net-zero. 3. Economic & Environmental Impact - Strengthens resilience against projected deficits.[3] - Advances net-zero through efficient cooling/heat reuse. - Creates jobs in engineering, water systems, and digital sectors. - Aligns with UK priorities for sustainable AI/digital growth.[4] - Delivers OPEX savings (e.g., 15–30% cooling cost reductions via heat recovery; near-zero water bills in optimized setups). 4. Hypothetical 20MW Data Campus Example – North East England (Assumptions: Hybrid closed-loop/air-assist; PUE ~1.3; ~5–10 ha site; North East rainfall ~700–800 mm/year—favorable for capture and renewables synergy.) - Annual energy: ~175,200 MWh (20 MW IT load). - Recoverable reject heat: ~50–70 GWh/year (potential to heat ~2,500–4,000 homes). - Baseline evaporative water: 300–700 million litres/year. - Waterworks Model outcomes: - Closed-loop primary: <100,000 m³/year (~5–10% baseline). - Rainwater capture: ~20,000–50,000 m³/year (from roofs/hardstanding). - Net potable demand: Near-zero for cooling. - WUE: <0.5–1.0 L/kWh (industry-leading). - Overall: 80–95% savings vs. traditional; 5–8 year payback via water/heat benefits. Scalable, location-optimized proof-of-concept. 5. Implementation Roadmap - Phase 1: Feasibility studies, hydrology assessments, consultations with EA/Ofwat. - Phase 2: Pilot campus (e.g., North East for rainfall/renewables advantages). - Phase 3: Regulatory integration and local/national alignment. - Phase 4: Regional replication and scaling. 6. Cost & Budget Considerations (for Engineers & Infrastructure Planning) Data centre infrastructure demands significant upfront investment, but the Waterworks Model mitigates long-term costs through efficiency gains and revenue opportunities. - **Overall Build Costs**: UK data centre shell/core construction averages £7–14 million per MW (2025–2026 figures; higher in London/prime sites; AI fit-out adds up to £25M/MW extra).[Sources: Turner & Townsend, Optrium, JLL, Site Ltd] - **Water Infrastructure Add-Ons**: - Closed-loop cooling hubs: 10–30% CAPEX premium vs. traditional evaporative but 70–95% water/OPEX savings (payback 3–7 years via reduced makeup water and treatment). - Rainwater harvesting (commercial scale): £7,000–£70,000+ per system (e.g., 6,000–50,000L tanks + pumps/filters; faster ROI in high-rainfall North East). - Heat recovery systems: £190,000–£250,000 per MW heat supplied; potential annual revenue £0.5–1M per 10 MW IT load from district heating sales (payback 6–15 years; grants like Green Heat Network Fund accelerate). - **20MW Example Budget Breakdown (Estimates)**: - Total CAPEX: £140–280 million (shell/core + fit-out). - Waterworks add-ons: +5–15% (£7–42 million) for closed-loop, rainwater, heat recovery. - OPEX savings: 15–30% on cooling/energy; near-zero water costs; heat revenue offsets 10–20% annual bills. - ROI: 5–10 years (stronger with incentives; e.g., AI Growth Zones reduce power costs £14–24/MWh). - Funding Pathways: Ofwat green grants, WSIP, Green Heat Network Fund (£65M+ precedents), tax credits for net-zero tech. This model turns sustainability into a competitive edge: lower lifetime costs, regulatory compliance, and new revenue from heat/water circularity. References [1] techUK (18 August 2025). Understanding Data Centre Water Use in England. https://www.techuk.org/resource/techuk-report-understanding-data-centre-water-use-in-engl and.html [2] techUK (27 August 2025). Guest blog: Balancing Bytes and Drops – Understanding data centre water use in England. https://www.techuk.org/resource/guest-blog-balancing-bytes-and-drops-understanding-data- centre-water-use-in-england.html [3] Environment Agency (17 June 2025, updated October 2025). National Framework for Water Resources 2025: Water for Growth, Nature and a Resilient Future. https://www.gov.uk/government/publications/national-framework-for-water-resources-2025-w ater-for-growth-nature-and-a-resilient-future [4] Government Digital Sustainability Alliance (2025). Water Use in AI and Data Centres Report. https://assets.publishing.service.gov.uk/media/688cb407dc6688ed50878367/Water_use_in_ data_centre_and_AI_report.pdf