Norwegian aluminium producer Norsk Hydro has produced aluminium for the first time using HalZero, an electrolysis technology designed to eliminate direct carbon dioxide emissions. Separately, majority-owned Slovalco has begun restoring primary aluminium production in Slovakia through a planned €100 million restart. The initiatives involve developing lower-emission production and returning existing capacity to operation.
HalZero moves beyond laboratory testing
Hydro reported the HalZero milestone in its third-quarter results after producing aluminium at its research facility in Porsgrunn, Norway. The technology is intended to replace the Hall-Héroult electrolysis process, which has been used for more than a century. In conventional production, carbon anodes react with oxygen released from alumina, generating carbon dioxide.
HalZero first converts alumina into aluminium chloride, which is then processed through an electrolysis system designed to retain chlorine and carbon in closed loops. The aim is to produce aluminium without the direct CO2 emissions associated with consuming carbon anodes. Hydro has developed the process since 2016 with Norwegian research institutions, including NTNU and SINTEF.
The demonstration shows that the core electrolysis process can produce aluminium beyond laboratory conditions, but the HalZero process is not commercially ready. Hydro said the current testing still produces some carbon dioxide because not all processing stages have been integrated into a closed-loop system. Norwegian state-owned agency Enova provided approximately €13.5 million in 2023 for the research facility, which began operating in January 2026.
Enova has since awarded a further €7.8 million for engineering and planning a larger industrial pilot. The next phase will integrate the main processing stages and test operational reliability, energy consumption, equipment durability and product quality. The funding does not approve construction of the pilot, and Hydro has announced neither a final investment decision nor a timetable for commercial deployment. HalZero must demonstrate lower emissions alongside competitive investment costs, operating expenses and production performance.
Slovalco targets a staged capacity restart
Slovalco began restarting production in late August 2026 under an agreement setting revised operating conditions. Primary aluminium production at the Slovak smelter had been suspended in 2022, after sharply higher electricity prices and insufficient compensation for indirect carbon costs undermined its competitiveness. The restart programme involves approximately €100 million in investment and is expected to support more than 200 jobs.
The first phase targets annual production capacity of 75,000 tonnes, compared with the smelter’s total installed capacity of approximately 175,000 tonnes. Hydro owns 55.3% of Slovalco, and Penta Investments holds the remaining 44.7%. A further 100,000 tonnes of annual capacity could be restored in a later phase, depending on electricity arrangements and regulatory conditions beyond 2030.
Power costs and carbon compensation shape operating conditions
The restart follows a long-term electricity purchase agreement with Slovak state-owned Vodohospodárska výstavba, giving the smelter greater visibility over future power costs. The wider framework also provides compensation for indirect carbon costs incurred when generators pass European Union 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 facilities using relatively low-carbon power can still face indirect carbon-cost exposure through their electricity procurement arrangements. Slovalco’s recovery also illustrates the limits of the Carbon Border Adjustment Mechanism (CBAM). Although aluminium is covered by CBAM, the mechanism does not directly remove European smelters’ electricity-cost disadvantages, leaving competitive power contracts and indirect carbon-cost compensation 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. This is relevant as demand for lower-carbon materials increases.
Hydro reports higher third-quarter earnings
Hydro reported third-quarter adjusted EBITDA of approximately €868 million, up from €573 million a year earlier. Higher aluminium prices, strong Norwegian production, and improved recycling and extrusion earnings supported the result. Norwegian smelters recorded their highest-ever liquid-metal production, while stronger margins supported downstream operations.
Free cash flow was approximately €134 million, reflecting increased working-capital requirements. Hydro lowered its full-year capital expenditure guidance to approximately €1.19 billion from €1.29 billion. Slovalco’s next major milestone is reaching 75,000 tonnes of annual capacity by February 2027, while HalZero’s priority is to demonstrate reliable and economic operation at industrial scale.