Data centres are one of the most demanding utility customer types in the UK. A single large data centre can consume as much electricity as a small town. Water demand for cooling is also substantial. The utility connection requirements are specialist, capital-intensive, and often on the critical path of the whole project.
This guide covers utility connections for UK data centres.
Power Demand
Data centre power demand is the dominant feature.
Small data centre: 1-5 MW.
Medium data centre: 10-30 MW.
Large data centre: 50-100 MW.
Hyperscale: 100+ MW, sometimes several hundred MW.
These loads are essentially continuous, 24/7/365, with very little diversification.
For context, a single 50 MW data centre uses as much electricity as around 35,000 homes.
Grid Connection Strategy
The grid connection is the dominant engineering challenge.
Small data centres (up to 5 MW): may be served by dedicated HV connection from local 33/11kV network.
Medium data centres: dedicated 33kV or 66kV connection with a customer HV substation.
Large data centres: dedicated 132kV or higher connection, sometimes requiring new grid infrastructure.
Hyperscale: connection at grid supply point, often with upstream network reinforcement.
Grid connection timeframes for large data centres can extend to 3-7 years, particularly in supply-constrained areas. Grid availability has become a major constraint on UK data centre site selection.
Resilience Requirements
Data centres require extreme resilience.
N+1 redundancy on all critical systems (one more component than strictly needed).
2N redundancy for highest-tier data centres (fully duplicated infrastructure).
Dual grid feeds from different substations.
UPS (uninterruptible power supplies) for seconds-level backup.
Diesel or gas generators for hours-level backup.
Fuel storage for days-level autonomy.
Data centre tier classifications (Tier I-IV from Uptime Institute) define the resilience level.
Cooling Infrastructure
Data centre heat must be removed.
Air-cooled systems: chilled water from central plant.
Water-cooled systems: direct liquid cooling of server racks.
Free cooling: using outside air when cool enough.
Evaporative cooling: using water evaporation for efficiency.
Cooling demand is typically 30-40 per cent of IT demand. A 50 MW data centre has 15-20 MW of cooling load.
Water Demand
Water is used for cooling.
Evaporative cooling: water consumed as it evaporates. Significant consumption.
Chilled water: closed loop, low net water consumption.
Backup fire suppression: sprinkler systems with pressurised supply.
Staff amenities: office and welfare water.
Typical water demand for a medium data centre: 5-50 megalitres per year depending on cooling technology.
Backup Generation
Backup generation is substantial.
Diesel generators: traditional choice, sized to meet full IT + cooling + auxiliary load.
Gas turbines: emerging for very large sites.
Battery storage: increasing for short-duration backup.
Hybrid systems: combinations for different outage durations.
For a 50 MW data centre, backup generation is typically 60-80 MW installed to allow N+1 operation.
Fuel storage for backup generators is typically sized for 48-96 hours of autonomy at full load.
Utility Connection Costs
For a new medium data centre (20 MW):
Grid connection: £5-15 million.
Customer substation: £2-5 million.
Backup generation: £15-30 million.
Cooling infrastructure: £25-60 million.
Water connection and treatment: £500k-2m.
Internal distribution: £8-20 million.
Total utility-related cost: £55-130 million, typically 15-25 per cent of total project cost.
The Grid Constraint
In 2026, grid capacity is a binding constraint on new UK data centres.
Popular locations (London, Manchester, Dublin) have limited headroom.
DNO connection queues for large loads can extend 2-5 years.
Some DNOs have paused new large connection applications in certain areas.
Network reinforcement costs can reach tens or hundreds of millions.
This is driving data centre developers to:
Sites with established HV infrastructure.
Secondary cities with available capacity.
Behind-the-meter generation to reduce grid dependence.
Negotiated capacity solutions with DNOs and National Grid.
Behind-the-Meter Generation
Increasingly, data centres are investing in on-site generation:
Solar PV: partial contribution.
On-site gas generation: base load.
Fuel cells: emerging technology.
Grid-scale battery storage: for time-shifting and resilience.
The goal is to reduce grid dependence and secure power availability in constrained areas.
Telecoms Resilience
Data centres need extreme telecoms resilience.
Multiple diverse fibre routes from different carriers.
Ideally three or more independent fibre entries.
Physical route separation (different buildings, different streets).
Carrier diversity.
Regular testing of failover.
Telecoms outages are as critical as power outages for data centre operators.
Planning Considerations
Data centres face specific planning challenges.
Visual impact of large buildings and plant.
Noise from cooling and generation plant.
Traffic for staff and deliveries.
Water demand scrutiny in water-stressed areas.
Grid impact and associated reinforcement works.
Impact on local energy infrastructure.
Many local authorities now have specific policies on data centres, some restricting them in certain locations.
Sustainability
Data centre sustainability is increasingly scrutinised.
PUE (Power Usage Effectiveness): metric of efficiency. Target 1.2 or lower for modern facilities.
Carbon intensity of grid supply.
Water use efficiency.
Heat recovery: using waste heat for district heating, horticulture, or other uses.
Renewable energy matching: 24/7 matching of supply to renewable generation.
Some authorities are requiring heat recovery or carbon neutrality as conditions of planning approval.
Compliance Regime
Data centres face multiple compliance requirements:
ISO 27001 for information security.
Tier certification for resilience.
PCI DSS for payment processing.
GDPR for data protection.
Building regulations for construction.
Environmental permits for emissions, water use, and chemical storage.
H&S regulations for worker safety.
Operational Timescales
For a typical medium data centre development:
Site selection: 6-12 months.
Planning: 12-24 months.
Grid connection application: 12-36 months.
Design: 12-18 months.
Construction: 18-36 months.
Commissioning: 6-12 months.
Total: 4-8 years from concept to operational.
Grid connection is usually the critical path.
Common Pitfalls
Several issues come up repeatedly.
Site selection without grid capacity confirmation. Can result in multi-year delays or abandoned sites. See our take on IDNO vs DNO for alternative adoption routes on large loads.
Inadequate backup sizing. Fails under load or in extended outage.
Poor thermal design. Higher cooling costs and reliability issues.
Under-engineered telecoms. Single points of failure in critical communication paths.
Planning complications. Insufficient engagement with local authority on concerns.
Overlooked environmental compliance. Late-stage permitting delays.
The Bottom Line
Data centre utility connections are one of the most demanding utility projects in the UK. Grid capacity has become a binding constraint in many locations. Resilience, cooling, and power infrastructure drive significant capital cost. Developers succeeding with data centre projects are doing so by selecting sites with grid headroom, engaging early with DNOs and local authorities, investing in on-site generation and storage, and treating utility infrastructure as a core part of the development, not a support service. For any data centre project in the UK today, utility strategy is at the heart of project feasibility. For industrial neighbours facing similar grid constraints, see our guide to industrial and logistics utility connections.