The processes required to refine alumina from bauxite ore and to smelt aluminium from alumina require significant amounts of energy and depending on the energy source, significant emissions invariably result.
Our focus and importantly, that of operating partner Alcoa, is on decreasing GHG intensity via:
- increasing energy efficiency through process and technology improvements
- investigating alternative energy sources from low or no carbon-based generation, (renewable options to meet large volume energy requirements are limited in many regions)
- advancing technological solutions for GHG abatement.
A major challenge is balancing the need to ensure energy security with energy diversification. Opportunities to switch energy sources are restricted by:
- long-term energy contracts that exist at AWAC’s Western Australian refineries
- the need for base load electricity supply at the Portland smelter.
Despite these hurdles, Alcoa continue to pursue opportunities to reduce the carbon intensity of AWAC’s purchased electricity. Research is ongoing into whether using solar energy to assist power the calcination process is feasible and has the potential to reduce non-renewable energy consumption at the refineries and therefore reduce GHG emissions.
Results and goals
In 2018 AWAC's total (on a full facility basis) absolute greenhouse gas emissions from AWAC’s operations increased by approximately 10.5% to 12.5 million tonnes from 11.3 million tonnes of CO2 registered in 2017. The increase in emissions was largely due to the 48% increase in GHG at the Portland aluminium smelter as the result of a restoration of potline production lost in 2017 due to a damaging power outage. In 2018, Portlands production increased by approximately 47% compared to 2017.
|Greenhouse gas emissions |
AWAC Full Facility of tonnes of CO2 equivalents.
|Direct (Scope 1)||10,330,772||8,986,055||7,788,387||7,575,617||7,413,321|
|Indirect (Scope 2)||8,123,143||6,180,774||5,588,770||3,741,416||5,087,177|
|Indirect (Scope 3)||Not available||Not available||Not available||34,468,831||35,103,007|
Scope 1 (direct GHG) emissions are those released directly by AWACs’ sites through direct use of energy sources on-site such as natural gas. Scope 2 or indirect emissions are those from electricity generated by external energy suppliers that supply energy to AWAC’s sites and also associated with the generation of steam at the co-generation facilities located at the Pinjarra refinery.
In 2018 Scope 3 emissions have been calculated and reported for the second time and encompasses;
- Purchased goods and services
- Fuel and energy related activity, and
- Processing of sold goods.
The major contributor to the value of Scope 3 emissions is, processing of sold goods. Sales of alumina is the main product of AWAC. Alumina is used downstream by customers in the production of aluminium which is an energy intensive activity.
Emissions Calculation Methodology
The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard (Revised Edition), Australia - National Greenhouse and Energy Reporting Act, Brazil GHG Protocol Programme and The Climate Registry: General Reporting Protocol. Emission per source calculated by applying WRI Calculation Tool