Synergies between Data Centres and Energy Systems - Final Report (European Commission, DG CNECT)

Overview

The study explores how data centres can be more effectively integrated into energy networks to reach the Green Deal and Digital Decade goal of extremely energy-efficient, climate-neutral data centres by 2030. The focus is how local energy systems can use the waste heat and water generated by data centre operations. It has five work packages: comprehensive mapping, drivers and obstacles, comparison with other energy and emission-intensive sectors, case studies and policy recommendations. It was prepared by EY, the Borderstep Institute, AIT, RP legalitax and Prof. Catherine Banet and does not reflect the official position of the European Commission.

In heat systems, waste heat recovery remains largely underused. Effectiveness depends on the cooling technique: liquid cooling (on-chip, immersion) versus air cooling determines the temperature of the waste heat, and because heat is often needed at a much higher temperature, heat pumps are crucial. Options are a central heat pump for a heat network or decentralised pumps in 4th and 5th generation networks. Data centres have a flat load profile while heat demand varies with outdoor temperature, so seasonal mismatch calls for heat storage. Almost 70 research and industry projects were identified; over 60% of stakeholders rated heat reuse technically viable but only about 20% economically viable.

On electricity, local renewables, demand response and 24/7 carbon-free electricity (CFE) stand out. The research indicates that a combination of wind, solar and battery storage can achieve 24/7 climate-neutral energy for data centres at minimal additional cost, with more granular green PPAs and flexibility services recommended. On water, evaporative cooling, air humidification and indirect consumption for electricity generation create problems; closed-loop, free cooling and warm-water cooling are among the remedies. Most participants regard technological water saving as feasible today but only a third consider it economically viable.

The legal analysis shows that the lack of a legally binding data centre definition at Member State level causes classification problems for land planning and taxation. From seven other industrial sectors 35 best available techniques (BAT) were identified and eight analysed in detail. The policy recommendations form 19 actionable advices, 11 legal and eight non-legal, under R&D, engagement and coordination. The study sets no target value or standard; it is a mapping, assessment and recommendation study.

Key points

1. Even air-cooled data centres can supply waste heat at about 30-35 C year-round as a heat-pump source, enabling high annual COPs; options are central heat pumps feeding 60-80 C networks or direct feed into 4th/5th generation cold networks.
2. High waste-heat utilisation needs heat storage or a data centre sized small relative to the heat demand area, because heat demand varies with outdoor temperature; for very large (tens to hundreds of MW) data centres only a few locations exist where waste heat can be used in a meaningful proportion.
3. 69 heat-reuse projects/initiatives were identified (41 industry, 28 research), with a sharp increase between 2015 and 2022.
4. In the stakeholder survey, over 60% rated heat reuse technically viable today but only about 20% economically viable.
5. Key levers identified: E1 local renewables, E2 demand response, E3 24/7 carbon-free electricity, E4 efficiency; H1-H3 heat network integration; W1 water reduction, W2 alternative water sources.
6. On the electricity side 28 industry and research projects were identified, half initiated by industry; stakeholders rated 24/7 green electricity and power flexibility much less important than heat reuse and not yet technically feasible in the short term.
7. On water most participants regard technological water saving as feasible today but only a third consider it economically viable; water prices are higher in scarce regions and low elsewhere, giving little incentive.
8. 35 BATs were identified from seven other sectors and eight analysed in detail; CHP and heat pumps can give significant efficiency gains if nearby heat consumers can be found.
9. Policy recommendations form 19 actionable advices (11 legal, 8 non-legal); there is no legally binding data centre definition at Member State level.

Using it in design

• When choosing cooling architecture assess waste heat temperature early: liquid cooling gives higher temperatures, even air cooling can give about 30-35 C as a heat-pump source; position the heat pump for the receiving network temperature (60-80 C or 4th/5th generation).
• In waste heat projects evaluate distance to the off-taker, heat losses and the seasonal demand profile; heat storage or limiting the data centre size to heat demand may be necessary.
• For a 24/7 carbon-free electricity target add local renewables, battery storage, granular PPA options and demand response capability (shifting workloads in time and geography) to the design.
• To reduce water use evaluate closed-loop, free cooling and warm-water cooling; in water-scarce regions consider alternative sources (treated wastewater, seawater) and allow for added treatment cost.
• In site selection make proximity to a heat network or heat off-takers (housing, agriculture, aquaculture) a criterion, and check how the local legal framework classifies data centres (tax, planning).

Who should read it

Designers, investors and policy teams setting data centre site, cooling and energy strategy.

Document contents

1. Executive Summary
2. 1. Introduction: purpose, overview, objectives and scope of the study
3. 2. Task 1: Comprehensive mapping, feasibility and effectiveness of integrating data centres into energy and water systems
4. 3. Task 2: Mapping of drivers, obstacles and potential opportunities
5. 4. Task 3: Comparison with other energy and emission-intensive sectors
6. 5. Task 4: Case studies
7. 6. Task 5: Policy recommendations
8. Annex 1: Regulatory analysis
9. Annex 2: Identified drivers and obstacles
10. Annex 3: Matrix of recommendations

Related standards

• Directive (EU) 2023/1791
• EN 50600-4-6

Read the document

Publication details

Authors

Axel Wion; Dennis Heatubun; Simon Hinterholzer; Ralf-Roman Schmidt; Nicolas Pardo-Garcia; Nicolas Marx; Verena Alton; Carla Bonacci; Catherine Banet

Publisher

European Commission, DG CNECT (EY, Borderstep Institute, AIT, RP legalitax)

Year

2025

Document number

KK-09-24-652-EN-N

Document language

English

Source type

Government / public

Access

Open licence — downloadable

DOI

10.2759/359565

Licence

CC BY 4.0 — share with attribution

Licence evidence

op.europa.eu

Citation