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 2020 was 2.13 t CO2-e / per tonne of aluminium produced. NZAS decreased the metal production by 18,133 tonnes in 2020 compared to 2019 due to ceasing operation of Line 4 in April 2020. This line was not re-started.
In the year ending 31 December 2020 the average energy use was 72 GJ per tonne of aluminium produced.