Greenhouse Gas and Energy
NZAS’s greenhouse gas (GHG) emissions are reported to the New Zealand Environmental Protection Agency and are calculated using an agreed methodology approved by the Intergovernmental Panel on Climate Change. The methodology calculates the tonnes of carbon dioxide equivalents (CO2-e) produced by the smelter from the consumption of fuels such as diesel, liquid petroleum gas and fuel oil, carbon anodes, electrical energy use and the generation of perfluorocarbon (PFC) gases.
The total calculated carbon dioxide equivalent discharge from NZAS during the year ending 31 December 2018 was 2.04 t CO2-e / per tonne of aluminium produced. NZAS increased the metal production by 3,936 tonnes in 2018 compared to 2017 due to restarting 44 cells in Line 4 between October and December 2018.
In the year ending 31st December 2018 the average energy use was 71 GJ per tonne of aluminium produced.