The Green MP 
Looking beyond the Google case, the discussions highlighted two distinct approaches. On the one hand, Joëlle Welfring argues that Luxembourg should impose the most stringent environmental standards and ensure that the costs incurred by this infrastructure are not borne by the public purse. On the other hand, Lex Delles emphasises the strategic importance of digital infrastructure for the country and for Europe, whilst affirming his desire to guide its development through improved energy efficiency, greater use of renewable energy and the systematic recovery of waste heat. As the project progresses through the authorisation process, the key issue will be less about whether Luxembourg wishes to host new data centres and more about determining the conditions under which these can be sustainably integrated into the national energy model.
Energy efficiency deemed to have room for improvement
Joëlle Welfring’s primary concern is the PUE (Power Usage Effectiveness) index, which measures a data centre’s energy efficiency. The Google project has a PUE of 1.3, a figure the MP considers insufficient by current standards. She points out that the European average is estimated at 1.15 and that Google itself achieves an average PUE of 1.10 at other sites.
When asked about the possibility of setting more ambitious performance targets and the scope for manoeuvre still available within the framework of the ongoing procedure, Lex Delles did not provide a direct answer. He emphasised the need to adopt the most efficient cooling technologies in order to reduce overall energy consumption. In his view, the aim is to balance energy efficiency, climate targets and compliance with European standards, particularly with a view to ‘Net Zero 2030’. He also stressed that technological choices must be assessed as a whole, taking into account the trade-offs between electricity consumption and water consumption.
Monitoring electricity consumption
The second point raised by the MP concerns the scale of the future centre’s electricity consumption. At around 1,000GWh per year, the project could, according to her calculations, consume as much electricity as all Luxembourg households combined. Joëlle Welfring questions the actual cost of this consumption to the public purse. In particular, she asks whether the costs associated with renewable energy compensation schemes and electricity imports – which she estimates at around 14 million euros – will be borne by Google.
Once again, the minister chose to frame the debate in strategic terms. In his view, the development of data storage and processing capabilities is a matter of sovereignty for both Luxembourg and Europe. He acknowledges, however, that the network’s capacity is not unlimited and that every new project must be carefully planned. This planning involves, in particular, strengthening the electricity infrastructure and cross-border interconnections – especially with Germany – in order to secure the country’s energy supply.
Waste heat as a focal point
It is on the issue of waste heat that the positions appear to be closest. The MP points out that the heat produced by the centre could provide heating for up to 10,000 households. However, she is seeking further details on the practical arrangements for recovering the heat, the necessary infrastructure and the safeguards required to turn this potential into reality.
Lex Delles has made this issue a central focus of his strategy. He believes that the heat generated by data centres should no longer be viewed as wasted energy, but as a local resource. Discussions are already underway to integrate future centres into district heating networks, particularly in Bettembourg and around the Bissen project, he explained. According to him, proximity to residential or industrial areas capable of utilising this heat is now a key planning criterion.
