Data centres are rapidly becoming one of the most energy- and water-intensive components of the digital economy, yet their cooling systems remain largely invisible in infrastructure and climate policy. While advanced cooling technologies can significantly reduce energy and resource use, the UK lacks a national framework to guide their adoption or measure their environmental impact. Here, Dr Dlzar Al Kez and Professor Aoife Foley explore how data centres can be cooled more efficiently and outline how cooling policy can be integrated into the national infrastructure agenda.

• Data centres form the physical backbone of the internet and power AI, cloud, and digital services.
• Cooling can account for 30–50% of a facility’s electricity use and up to 26 million litres of water annually.
• Policymakers should treat data centre cooling as critical infrastructure to align with net zero goals.

The heat we don’t see

Data centres are vast buildings filled with machines that never sleep, drawing electricity around the clock and radiating enough heat to warm entire neighbourhoods. They are the physical backbone of the internet, and the thermal energy they generate is rapidly becoming a blind spot in UK climate and infrastructure policy.

As AI systems, cloud computing, and digital public services expand, the machines that power them are getting hotter. Keeping them cool is becoming more difficult, more expensive, and more environmentally damaging. Yet the technologies that perform this essential work remain almost entirely absent from planning policy, sustainability reporting, or net zero infrastructure strategies. That omission is no longer sustainable. Cooling is now a frontline issue in energy planning, climate adaptation, and digital resilience.

Silent systems, growing impact

Data centres are designed to operate discreetly. But their heat does not vanish; it must be removed continuously and with precision. Until recently, most facilities relied on raised-floor cooling, where chilled air is pumped beneath server racks and hot air is extracted mechanically. This method now struggles to keep pace with rising computing densities.

To meet higher thermal demands, operators are turning to advanced cooling systems such as direct-to-chip liquid cooling and full immersion technologies, where servers are submerged in specialised fluids. These methods can reduce energy consumption significantly, but uptake remains fragmented and poorly regulated. Many facilities still rely on outdated systems that consume excessive electricity and water, particularly during peak loads, while escaping any meaningful disclosure requirements.

Globally, data centres already account for an estimated 1 to 2% of electricity demand, a share that is rising. In the UK, the growth of artificial intelligence and edge computing means that cooling energy use is accelerating in both the private and public sectors.

Research from The University of Manchester, has examined how emerging cooling technologies and overlooked environmental risks are reshaping the sustainability profile of AI-intensive data centres. The study found that direct-to-chip and immersion cooling systems can reduce cooling-related electricity use by up to 40–60% compared to traditional chilled-air methods, offering a clear pathway to lower emissions in high-density facilities and supporting the UK’s broader net zero commitments. At the same time, the research identified critical regulatory blind spots, particularly around water use in evaporative cooling systems, which can consume up to 26 million litres of water per megawatt annually, with little or no reporting required. These findings highlight the need for integrated infrastructure planning that supports advanced cooling deployment and for national disclosure standards that make water and refrigerant use transparent to planners, regulators, and communities.

A missing framework

While data centres are now recognised as critical infrastructure under the UK’s Planning and Infrastructure Bill and recent updates to the National Planning Policy Framework (NPPF), their cooling systems remain a major blind spot. This new designation brings stronger planning support and faster development routes. However, cooling is rarely treated as a distinct infrastructure challenge. Without dedicated national frameworks, the environmental footprint of cooling will continue to escape meaningful oversight.

Some industry leaders are experimenting with waste heat recovery, integrating server exhaust into heating networks. Others are deploying AI-based controls to optimise cooling performance in real time. In cities like London and Manchester, pilot projects are exploring how to connect data centre heat to nearby residential or public buildings. Internationally, countries such as Denmark and Sweden are already incorporating data centre heat into municipal district heating systems. These efforts are promising, but they remain isolated and voluntary. Without a consistent regulatory framework, clear performance metrics, or national planning guidance, their broader impact will remain limited.

A national policy response

Addressing the environmental impact of data centre cooling requires treating it as a core infrastructure issue. This means embedding cooling into national planning decisions, climate regulation, and digital transformation policy.

First, environmental assessments for new data centres should include mandatory disclosure of cooling systems, including projected energy and water use, resilience to high ambient temperatures and climate-related disruptions, and potential for heat reuse. Planning authorities need clear criteria to evaluate the long-term impact of cooling infrastructure. The Greater London Authority’s “cooling hierarchy” and energy assessment guidance offer a strong starting point, but could be expanded to include lifecycle energy use, water consumption for cooling, resilience to extreme heat events, and quantified potential for waste heat reuse. These additions would improve the ability to assess long-term sustainability and infrastructure implications.

Second, retrofitting incentives should be extended to thermal systems. Many existing facilities are unable to meet modern efficiency benchmarks, but retrofitting with hybrid or liquid cooling systems could dramatically reduce energy use, if supported by appropriate investment frameworks such as targeted retrofit grants, or low-interest loans for sustainable infrastructure upgrades. This is especially important given the long operational lifespan of many data centre facilities, which can stretch for decades.

Third, cooling must be planned alongside other digital infrastructure components. Just as the UK coordinates broadband rollout and grid integration, it should also support cooling supply chains, workforce training, and interoperability with local energy systems. Cooling guidance could be embedded in the net zero Strategy or aligned with the National Infrastructure Commission’s digital infrastructure frameworks.

Finally, national reporting and benchmarking standards are urgently needed. Currently, there is no requirement for operators to disclose key metrics such as water usage, refrigerant types, or heat recovery potential. A reporting framework led by the Department for Energy Security and Net Zero (DESNZ) or the Environment Agency could include metrics such as Power Usage Effectiveness (PUE), Water Usage Effectiveness (WUE), Global Warming Potential (GWP) of refrigerants, and annual heat recovery rates. This would provide developers with clarity, support policymakers with data, and enable more sustainable design choices across the sector.

A path to leadership

The UK has already demonstrated leadership in renewable energy deployment, energy market reform, and AI regulation. Now it must lead again, by integrating cooling policy into the national infrastructure agenda. A coordinated, standards-based, and forward-looking strategy would not only reduce emissions but also strengthen the resilience and global competitiveness of the UK’s digital economy.

Recognising cooling as infrastructure, not as a niche engineering concern, is the first step toward building a digital future that is sustainable by design. Without effective policy, these facilities risk becoming both a bottleneck for digital growth and a liability for the environment.