What reporting now applies?
The EU has set the pace. Its Energy Efficiency Directive delegated regulation (EU 2024/1364) requires larger data centres, above 500 kW of IT load, to report energy consumption, power usage effectiveness (PUE) and water usage effectiveness (WUE) each year. It applies to EU sites and sets a template the rest of the market is watching.
In the UK, larger operators already fall under ESOS, the mandatory energy audit, and the sector's Climate Change Agreement carries an energy-efficiency target of 14.5 percent against a 2022 baseline by the end of 2030 in exchange for Climate Change Levy relief.
Why is water the new pressure point?
Cooling makes data centres water-hungry, and the geography is working against them: a large majority of water-intensive developments are proposed for areas that are already water-stressed. That puts water draw at the centre of planning scrutiny.
The industry's own Climate Neutral Data Centre Pact has responded with a target of no more than 0.4 litres of water per kWh for new facilities in cool climates that use potable water in water-stressed areas, from 1 January 2025, and UK water-use reporting for the sector is being actively developed.
What does CNI status change?
In September 2024, UK data centres were designated Critical National Infrastructure, the first new CNI sector in nearly a decade. The designation raises expectations on resilience, continuity and incident mitigation.
That matters because cooling sits at the intersection of resilience and efficiency: it is both a major energy and water cost and a leading cause of outages, so changes to cooling have to improve efficiency without ever putting uptime at risk.
How do you cut water and energy without risking uptime?
The order matters: protect resilience and compliance first, then add the efficiency gain. On the water side, holding cooling systems safely at higher cycles of concentration reduces the make-up water drawn and the blow-down sent to drain, while keeping Legionella control intact.
You can size the water and chemical cost of a cooling tower, and the reducible share, with our cooling tower water and cost calculator, then confirm what is achievable per site.