Greenhouse Gas and Energy
NZAS’ 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 2019 was 2.10 t CO2-e / per tonne of aluminium produced. NZAS increased the metal production by 10,803 tonnes in 2019 compared to 2018 due to a full year of operating Line 4.
In the year ending 31 December 2019 the average energy use was 72 GJ per tonne of aluminium produced.