sible if nearby demand is present Furthermore investments in e g district heating require signifcant capital costs which will have to be carried by other sectors Finally longterm and transparent contracts will need to be established to create a viable business model for nonferrous metals producers BO X 13 A urubis Hamburg district heating In 2018 A urubis started with the delivery of industrial waste heat to the energy supply in the Hamburg district of Hafencity East The partnership between A urubis and the district sees industrial waste heat from the copper plant in Hamburg providing energyefcient district heating to Hafencity East For this purpose A urubis e xtracts heat that is formed when sulfur dio xide a byproduct of copper smelting is converted to sulfuric acid This industrial waste heat is nearly free of CO 2 and utilising it will over time reduce CO 2 emissions by more than 20 000 t per year About half of this reduction results from the replacement of natural gas used to produce steam on the A urubis plant premises while the other half is saved by delivering the waste heat to the district A urubis will deliver the heat to its plant boundaries Enercity a local energy provider will collect the heat secure it and transport it further to the area that will use it 230 230 A urubis 2017 The investment was more than 20 million for A urubis and additional 20 million for the partner company A urubis is working on the ne xt phase to utilise the full heat potential which will further save up to 140 000 t of CO 2 annually BO X 12 Zinc smelter virtual battery 228 The electrolysis section of zinc smelters can be switched down to a holding pattern at short notice This service is currently commercialized as emergency switchof capacity European zinc smelters are typically bottleneck ed on their electrolysis plants as a result any reduction in power means a reduction in production Therefore the zinc smelters incur high costs when decreasing power since the production of zinc is lost By investing in additional cell house and intermediate storage capacity this service can be supplied at a very low oper ational cost and without zinc capacity loss The Investment lies in line with investments for pumpedstorage power plant 229 Specifc investments depend on specifc plant setup availability of surplus power supply to the plant and desired uptimedowntime profle A 300kty zinc smelter could thus provide a fe xibility of up to 80 MW power and around 3500 MWh energy storage An investment in a specifc plant can decrease investments in upgrading the grid capacity and therefore in the end be more cash efective W aste heat to other sectors While waste heat recovery is important to improve the energyefciency of metals produc tion itself there is limited potential for lowtemperature heat which has no direct applica tion in metals production to be used by other sectors e g buildings This will only be pos 228 Nyrstar 229 R eference for pumped power station from Nik olaides and P oullik as 2017 MET ALS IN A CLIMA TE NEUTRAL EUROPE A 2050 BL UEPRINT 61