A sustainability report rarely specifies what has changed. ArcelorMittal Luxembourg’s report, however, reveals a shift. Several projects still described as ‘works in progress’ in 2024 had, by 2025, become facilities that had been tested, commissioned or were in full operation. But Belval, Differdange and the solar power project are not merely environmental initiatives. They are becoming the visible components of a single challenge: maintaining a steel industry in Luxembourg within a Europe that consumes little, faces production pressures and must invest in decarbonisation.
The document published by ArcelorMittal Luxembourg does not yet constitute a full CSRD report. The 2025 report continues to be prepared in accordance with the Global Reporting Initiative guidelines, as the transposition of the European CSRD and CS3D directives into Luxembourg law has been deferred following the ‘Stop-The-Clock’ Omnibus Directive of April 2025. This detail is not merely regulatory. It also reflects the nature of the exercise: the Luxembourg report remains a tool for continuity, dialogue and local presentation, at a time when the European framework for sustainability reporting continues to evolve.
Belval and Differdange: examples of the challenges involved
In 2025, the narrative shifts. In Belval, construction of the new electric furnace has been completed and the plant underwent its first operational trials at the end of the year. The facility has been gradually ramping up production since then. In the annual report, SteelUp is described as a key programme for the modernisation of the steelworks. It is intended to secure and relocate the production of semi-finished products, particularly those destined for the Rodange rolling mill, improve industrial performance and accelerate decarbonisation through production that relies more heavily on the electric furnace process.
However, this transformation is not proceeding smoothly. ArcelorMittal reports that its operational performance in 2025 was significantly affected by SteelUp, with prolonged shutdowns and constraints on the availability of semi-finished products. Total production at the Belval and Differdange steelworks stood at 1.84 million tonnes, down 1.6% on 2024. Total shipments from ArcelorMittal Belval & Differdange reached 1.78 million tonnes, in line with the previous year. The average selling price fell to €791 per tonne, €23 less than in 2024. Investments totalled €86.6m within this scope, including €25m for SteelUp.
This is where the report becomes more than just a sustainability brochure. It shows that industrial transition does not simply run parallel to business activity: it disrupts, reorganises and shapes it. Producing differently involves halting, replacing, testing, adjusting and investing in a market that does not naturally support such efforts. The year 2025 is described as a year of transition and severe constraints, dominated by SteelUp and a deteriorating market. Sustainability therefore appears less as a mere image booster than as a prerequisite for competitiveness and industrial continuity.
The broader context reinforces this interpretation. The 2025 report describes a global steel sector that has reached a production plateau following the post-Covid recovery. Global crude steel production is set to fall to 1,849 million tonnes in 2025, a decline of around 2% compared with 2024. In Europe, the situation is more structural. EU27 crude steel production falls to 126 million tonnes in 2025, down from 130 million in 2024, and remains well below the 2021 peak. ArcelorMittal cites high energy costs, sluggish demand, a low-carbon transition that remains costly, and increased international competition.
Luxembourg continues to stand apart. Crude steel production there remains at around 1.8 to 1.9 million tonnes per year over the period 2020–2025. This stability contrasts with the more pronounced fluctuations observed elsewhere in Europe. It is due in particular to a production system based predominantly on electric furnaces, the extensive use of recycled scrap metal and a focus on higher value-added products. However, this relative stability does not fully protect the country. The report highlights the sensitivity of Luxembourg’s activities to the construction cycle, competitive pressure from imports and the still high level of energy costs.
It’s not just about carbon
This is the second key takeaway from the document. Sustainability is not just about carbon; it concerns the very economic model of Luxembourg’s steel industry. Belval is a world leader in large-dimension sheet piles. Differdange produces some of the tallest and heaviest beams in the world. Rodange remains specialised in rails and special-purpose sections. Bissen produces wire for agriculture and industry, as well as metal fibres for the construction sector. Luxembourg cannot compete on volume. It therefore seeks to defend its position through specialisation, quality, circularity, infrastructure and sustainable construction.
In Differdange, the other key development for 2025 centres on noise pollution. The dust extraction system there has now been completed. ArcelorMittal states that it should reduce fugitive emissions generated by the site’s operations by 80%. The group emphasises the nature of the project: it is not aimed at producing more steel or improving profit margins. It is an environmental investment, focused on the relationship with the communities in which the company operates. In a country where urbanisation has brought former industrial sites closer to residential areas, this factor carries as much weight as the tonnes of steel produced.
The same approach is evident at the European Logistics Centre. The 5MWp solar power plant, installed on the site’s rooftops, was commissioned in March 2025 and had generated nearly 3GWh by the end of December, exceeding the site’s electricity requirements. The surplus energy was exported and utilised at other sites in Luxembourg. Whilst the project does not have the industrial scale of SteelUp, it illustrates the same trend: sites are no longer described merely as production or storage units, but as places where energy, emissions and public acceptance also come into play.
Security: a sensitive issue
Safety is the most sensitive aspect of the report. The 2024 financial year was marked by the fatal accident that occurred on 24 July at the Belval steelworks, when a subcontractor was struck by a block that had fallen from a crane. In 2025, ArcelorMittal is highlighting the roll-out of the One Culture Roadmap, structured around safety governance, leadership skills development, risk management, Process Safety Management and the integration of safety into cross-functional roles. The press release states that the lost-time accident frequency rate remained at 0.23, the same as in 2024.
Once again, the report must be interpreted with caution. It highlights a fall in the number of accidents and record numbers of accident-free days with lost time at several sites. However, it also points to the persistence of incidents with a high potential for severity and the need to continue risk management measures, particularly amongst subcontractors. Safety is therefore not merely a social indicator in a sustainability report. It has become a test of industrial governance, following a year that has served as a stark reminder that the transformation of a steelworks cannot be measured solely in terms of investment or tonnes produced.
In the press release issued alongside the report, the vice-president of ArcelorMittal Luxembourg, 
