A Thousand Gigawatt Hours

The plans for a Google data centre in Bissen returned to parliament on Thursday morning, and the numbers are striking. The facility, if built as currently designed, would consume an estimated 1'000 gigawatt hours of electricity per year. That is roughly equivalent to the combined consumption of every household in Luxembourg.[1]

Green MP Joelley Welfring reserved her sharpest criticism for the project's energy efficiency. The Bissen site, she said, does not meet European standards when compared to other Google facilities. The electricity will come entirely from renewable sources, but there is no obligation to produce even part of it within Luxembourg's borders. The power will be purchased, not generated.[2]

Then there is the heat. Data centres produce enormous quantities of waste heat as a byproduct of computation. Welfring emphasised that the heat generated by the Bissen facility could warm thousands of households, and urged the project to incorporate heat recovery. The technology exists. District heating networks that use data centre waste heat already operate in parts of Scandinavia and the Netherlands. Luxembourg has no national framework for this yet.[3]

Economy Minister Lex Delles responded with a measured defence. The authorisation procedure for the Bissen site dates back to 2020, he noted, and technical standards have advanced since then. He partially understood the criticism but pointed to the project's trajectory. Luxembourg's electricity supply capacity would need to increase regardless, as it has with previous infrastructure projects, including the 380 kV interconnector line to Germany.[4]

Delles framed the project within a larger argument about digital sovereignty. Europe needs data centres to avoid dependence on infrastructure concentrated elsewhere. Luxembourg's role, he suggested, is not to attract the largest facilities but to build reliable, secure, renewable-powered infrastructure. The waste heat should be recycled where possible, but, he added, "not at all costs." A national framework for heat recovery does not yet exist.[5]

The argument is not new. It is the argument that every small country faces when a large company proposes a large facility: the balance between sovereignty and dependence, between economic development and environmental cost, between what is possible now and what should be possible later. Google first announced the Bissen data centre in 2018. The project has been delayed by planning disputes, environmental concerns, and questions about water usage. Each year, the estimated energy consumption has grown.[6]

What makes this particular debate unusual is the scale. Luxembourg is a country of approximately 670'000 people. A single facility consuming as much electricity as every household in the country is not a marginal addition to the grid. It is a structural change. The 380 kV interconnector to Germany, which Delles referenced, was built to import electricity, not to accommodate domestic demand growth of this magnitude. The renewable energy certificates will be purchased, but the physical electrons will come from wherever the European grid can supply them.[7]

The waste heat question is perhaps the most telling. A data centre that consumes 1'000 GWh per year produces heat on a similar scale. In Copenhagen, the Facebook data centre in Odense provides heat to 6'500 households through district heating. In the Netherlands, Microsoft's data centres in the North Holland region feed waste heat into greenhouses. The technology is proven. The question is whether Luxembourg will require it, and whether Google will build it in.[8]

Delles said the government wants an energy-efficient data centre. Welfring said the current plan is not one. Both statements can be true. The gap between them is where the next decision will be made.