Superior Technology for Energy-efficient Aluminium Production (STEP)

Superior Technology for Energy-efficient aluminim Production (STEP) has contributed to the development of energy efficient production of primary aluminium. The project is well integrated with Hydros strategic ambitions for being world leading. Achieved innovations represent important and necessary steps towards realization of ultra-low specific energy consumption. Industrially the best figures are 12.5-13 kWh/kg Al as of today. Hydro has, as a result of dedicated R&D; production units today that lie well below this. Further; reduction of the carbon footprint has been important. Focus has been on thermal conditions and has built on earlier knowledge from development of the latest technology platforms such as HAL4e (Karmøy Technology Pilot). Project results have also been implemented or will be used in improvement work for all Hydro smelters.

Achieved knowledge, new models and equipment has given new understanding and means for control of important mechanisms that influence the heat balance and energy efficiency. The project has contributed to maintain and develop competence internally and with key external partners that Hydro for certain will collaborate more with in the future. Several results from this project are already in use. This will give invaluable input to further improvements. It is not possible to quantify the impact on e.g. specific energy consumption or emission reductions (CO2 footprint), but that results achieved will have positive effects is certain. Hydro has through this project added important technology understanding and elements to our technology portfolio and thus strongly contributed to achieving a main ambition: to stay in the technological forefront, and to contribute to secure and to improve operations in Norway and abroad.

The project is designed to accelerate the development of energy-efficient technology elements within the frame of the Hall-Héroult process, in order to strengthen Hydro Aluminium's position as a provider of world leading electrolysis technology. The planned innovations represent steps towards realisation of Hydro's vision of ultra energy efficient aluminium production and ambition to become carbon neutral by 2020. The project aims at developing ideas concerning energy savings in electrolysis cells, which requires knowledge and design concepts beyond the present state-of-the-art. The project is divided into four main activities. 1) Superstructure heat management: aims at developing models for evaluation of superstructure thermal functionality 2) Anode design and assembly concepts: will explore the possibilities of reducing the ohmic resistance in the anode and anode assembly by developing concepts using new design, new materials, and carbon with higher conductivity. 3) Energy-efficient operation: will develop an improved cell control system based on information on current distribution between individual anodes 4) Sideledge and sidewall heat transfer: seeks to obtain better understanding of the sideledge and comprises prototyping of concepts for sidewall cooling. Implementation is expected to benefit current development of new technology platforms such as the Karmøy Technology Pilot and beyound. An energy reduction of only 0.6 kWh/kg Al (or 5% reduction compared to current top technology performance) is considered a considerable achievement and represents a value in the order of minimum 10-12 MNOK savings per year for the planned pilot and a further >100 MNOK for entire the Norwegian production system at a similar energy reduction.