The Hydro HalZero technology will fully decarbonize the smelting of aluminium, eliminating emissions from both electrolysis and anode baking, resulting in emission-free aluminium.  

Status and way forward 

The HalZero technology is based on converting alumina to aluminium chloride prior to electrolysis in a process where chlorine and carbon are kept in a closed loop. Carbon and chlorine are recycled and reused again and again, thus eliminating emissions of CO2 and emitting oxygen instead. 

Hydro technologists have succeeded in modeling and verifying the HalZero process at our research and development laboratory in Porsgrunn, Norway. The results of the initial test phase were promising, and the process design studies have shown that an industrial-scale HalZero plant will have power consumption and operating expenditure about the same as current electrolysis technology.  Capital expenditure is expected to be comparable to new conventional smelter capacity. The HalZero process will be applicable for greenfield aluminium plants or brownfield replacement of obsolete potlines, where the smelter infrastructure can be re-used. 

Significant research is still required to mature the HalZero process toward industrialization. The components of the HalZero technology are at different Technology Readiness Levels and there is still significant risk associated with the full process system. Pilot testing in laboratory scale is ongoing and if successful, the ambition is to produce first pilot volumes by 2025. Scaling up pilot testing will require significant investment and public-private partnerships. Hydro’s goal is to have an industrial-scale pilot up and running by 2030, making the HalZero technology viable for implementation in new electrolysis capacity from 2030 onwards.  

*The name HalZero alludes to the common way of naming Hydro Aluminium cell technology – HAL – and our promise to deliver zero emissions.