Norwegian primary aluminium producer Norsk Hydro has made aluminium for the first time using its HalZero electrolysis technology, while advancing a €100 million restart of primary production at Slovalco in Slovakia. Hydro reported the HalZero milestone at its research facility in Porsgrunn, in Norway. Separately, majority-owned Slovalco is restoring operations with a first-phase target of 75,000 tonnes of annual capacity.
HalZero Moves Beyond Laboratory Testing
HalZero is intended to replace the Hall-Héroult electrolysis process, which has been used for more than a century. Conventional production uses carbon anodes that react with oxygen released from alumina, generating carbon dioxide. Hydro’s alternative first converts alumina into aluminium chloride, then processes it through an electrolysis system designed to keep chlorine and carbon in closed loops.
Hydro has developed the process since 2016 with Norwegian research institutions, including the Norwegian University of Science and Technology (NTNU) and SINTEF. The latest production milestone demonstrates that its core electrolysis process can make aluminium beyond laboratory conditions. The HalZero process is not yet commercially ready, and Hydro said tests still produce some carbon dioxide because not all stages are integrated into a closed-loop system.
Norwegian state-owned agency Enova provided approximately €13.5 million in 2023 for the existing research facility, which began operating in January 2026. Enova has since awarded a further €7.8 million for engineering and planning work on a larger industrial pilot. The funding is not approval to build the pilot.
The next phase will integrate the main processing stages and test operational reliability, energy consumption, equipment durability and product quality. Hydro has not announced a final investment decision or a timetable for commercial deployment. The technology must demonstrate lower emissions while maintaining competitive investment costs, operating expenses and production performance.
Slovalco Restarts After the 2022 Production Suspension
Slovalco began restarting production in late August 2026 under an agreement setting revised operating conditions. The Slovak smelter had suspended primary aluminium production in 2022, after soaring electricity prices and insufficient compensation for indirect carbon costs weakened its competitiveness. The restart programme involves approximately €100 million in investment and is expected to support more than 200 jobs.
The first phase is targeting 75,000 tonnes of annual production capacity, against installed capacity of approximately 175,000 tonnes. Hydro owns 55.3% of Slovalco, while Penta Investments holds the remaining 44.7%. A further 100,000 tonnes of annual capacity could potentially be restored in a later phase, subject to electricity arrangements and regulatory conditions beyond 2030.
The restart follows a long-term electricity purchase agreement with Slovak state-owned Vodohospodárska výstavba, providing greater visibility over future power costs. The wider framework includes compensation for indirect carbon costs that arise when electricity generators pass EU Emissions Trading System (EU ETS) expenses through to wholesale electricity prices. The agreement was conditional on European Commission approval of the revised Slovak compensation scheme.
Aluminium smelting requires continuous, electricity-intensive operations, and even facilities using relatively low-carbon power can face indirect carbon-cost exposure through their electricity procurement arrangements. Slovalco’s recovery also highlights the limits of the EU’s Carbon Border Adjustment Mechanism (CBAM): although aluminium is covered, CBAM does not directly remove the electricity-cost disadvantages faced by European smelters. Competitive power contracts and compensation for indirect carbon costs therefore remain important to domestic production.
Restored primary aluminium capacity could improve access to regional metal supplies for European automotive manufacturers, electricity-network suppliers and renewable energy companies, particularly as demand for lower-carbon materials increases. Slovalco’s next major milestone is reaching 75,000 tonnes of annual capacity by February 2027. The potential later restoration of 100,000 tonnes remains dependent on electricity arrangements and regulatory conditions beyond 2030.
Hydro Reports Higher Adjusted EBITDA
Hydro reported third-quarter adjusted EBITDA of approximately €868 million, up from €573 million a year earlier. The company attributed the increase to higher aluminium prices, strong Norwegian production, and improved earnings from recycling and extrusion. Norwegian smelters recorded record liquid-metal production, while stronger margins supported downstream operations.
Free cash flow was approximately €134 million, reflecting increased working-capital requirements. Hydro also lowered its full-year capital expenditure guidance to approximately €1.19 billion, from €1.29 billion. Slovalco’s targeted production restart is a nearer-term development, while HalZero remains a research and development programme requiring further industrial testing.