Environmental Performance

Tiwai Pointer

NZAS has several Resource Management Act 1991 consents issued by Environment Southland for discharges to air, land and water.  NZAS reports monthly, quarterly and annually to Environment Southland on its environmental performance within these consents.

In 2018 NZAS did not receive any fines, judgements or penalties for failure to comply with applicable law.


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.


Spills to the Environment

There were no significant environmental spills to report in 2018.


Waste Management

NZAS continued its extensive waste recycling program during 2018 to manage its waste arisings in a manner that avoids, where practicably possible, disposal in landfill.  This strategy aims to reduce generation and take advantage of reuse, recycling and energy recovery opportunities.

All waste metal, paper, plastics, and cardboard are sorted separately and sent off-site to approved organisations for recycling.  During 2018 approximately 2,500 tonne of these materials were sent for re-processing.

During 2018 general waste, carbon material, and clean fill was deposited in separate storage cells at the NZAS landfill.  Cells at the landfill are managed to minimise exposed open faces and are progressively covered with gravel and/or wood chips to minimise fugitive dust.

This material deposited at the NZAS Landfill in 2018 comprised:

  • General Waste - 373m3
  • Clean Waste - 563m3
  • Carbon Material - 4771m3

Waste timber was stockpiled in the landfill for future chipping to be used as ground cover material on the carbon pile.  However, no waste timber was chipped in 2018.

An additional 100 tonnes of non-hazardous waste was deposited at the Invercargill City municipal landfill.

During 2018 the independent company Inalco processed all current arisings of dross and some of dross material that was containerised and stored on site prior to Inalco commencing operations at NZAS.  The long-term plan is for Inalco to process the remaining stored containerised dross and the landfilled Metal Reclamation Plant (MRP) stockpile.

During 2018 all Spent Cell Lining (SCL) generated was stored within existing dedicated buildings due to waiting on Basel Convention approvals prior to shipment of SCL material for re-processing.



NZAS is committed to preserving the biodiversity on Tiwai Peninsula.  NZAS continued to work with the New Zealand Department of Conservation for ongoing management of the Tiwai Peninsula.

Species of significance located within the proximity of the smelter are:

  • Asaphodes frivola moth
  • NZ iris
  • Euphorbia glauca (by Tiwai Wharf)
  • Black fronted tern
  • Southern NZ dotterel
  • Australasian bitten.

During 2018 NZAS took no specific actions for biodiversity sustainability programmes apart from general weed control on the Tiwai Peninsula.  The New Zealand Department of Conservation continued monthly checking of traps for stoats, weasels, ferrets and other pests on Tiwai Peninsula.