48 cells running on the HAL4e technology 123 k Whk g and 12 cells using the HAL4e Ultra technology 115118 k Whk g This technology will use 15 percent less energy for aluminium production than the global average providing the lowest CO 2 footprint in the world The pilot aims to set a new benchmark for emissions reducing direct CO 2 emissions to 140145k g CO 2 equivalents per k g aluminium or 0 8k g per kilo of aluminium below the current world average The true innovation of HAL4e is the unique combination of low energy consump tion high current density i e high productivity low C APEX i e compact footprint and low emissions There has been a strong focus to include as many digital and Industry 40 aspects in the pilot as possible mainly focusing on automation realtime connectivity and an enhanced control platform T otal costs are estimated at 442 million consisting of net project costs of 277 million and around 164 million in support from Norwegian government enterprise Enova This grant was essential in making the pilot possible given that industrial scale testing of new technologies is both capital and risk intensive 164 Figure 35 Norsk Hydro primary aluminium production source Norsk Hydro Inert noncarbon anodes Inert anodes are seen as the holy grail in the production of primary aluminium These inert anodes would replace the energyintensive production of carbon anodes and would 164 European Aluminium 2018b Norsk Hydro and V atne 2018 64 New processes in primary aluminium production incl copper electrolysis Primary aluminium production has seen large efciency gains since it was frst introduced Further efciency improvements become more difcult but there still e xists potential for improvements Higher efciency of primary aluminium electrolysis process L owering the temperature of primary aluminium production from 950C closer to the melt ing point of 680C while maintaining stable operation can bring about important energy savings Theoretically reducing the temperature to around melting point should decrease electricity use by 1015 MWht although in reality savings are lik ely to be around 0 7 MWht 5 Also energy from the superheated metal is generally used to remelt preloaded scrap in the casting house beneftting from its free energy 159 The chloride process developed by Alcoa between 19601980 based on the chlorination of refned aluminium o xide does tak e place at such lower temperatures In practice the chloride process has not been able to compete with the HallH e roult process and little information is available on industrial e xperience with the method The chloride process is adversely afected by raw materials impurities a number of unfortunate side reactions can occur and gaseous chlorine com pounds are generally to xic 160161 The application of dynamic A C magnetic feld in electrolysis cells can enable smaller elec trode separation and hence reduce energy losses Energy savings can be between 520 TRL stands at 34 This technology is lik ely not compatible with use of inert and wetted anodes see below 162 The physical design of anodes can be also altered to improve energy efciency of the Hall H e roult cells For e xample sloped and perforated anodes mak e electrolysis more efcient by allowing better circulation within the electrolyte bath while vertical electrode cells save energy by reducing heat loss and improving electrical conductivity 163 This new design of anodes will however also require a diferent type of cathode BO X 8 Norsk Hydro s K armoy T echnology plant During the last decade researchers in Nork s Hydro s technology centres have developed a new generation of electrolysis technology This aims to reduce both industry energy con sumption and emissions It is now being tested in a fullscale production plant The pilot was designed with an annual production capacity of appro ximately 75000 tonnes It consists of 159 Ibidem 160 Oye B 2019 161 The chloride process also has inert anodes but the carbochlorination process can produce high CO 2 concentrations in the process gas making it easier to implement CO 2 capture and storage Oye B 2019 162 Fraunhofer ISI 2019 163 IEA 2018 MET ALS IN A CLIMA TE NEUTRAL EUROPE A 2050 BL UEPRINT 53