Greenhouse Gas Emissions
Alcoa has long recognised the need to respond to the challenge of climate change. We took an early voluntary global leadership position on addressing climate change and reducing greenhouse gas (GHG)emissions, and have been successful in reducing our greenhouse footprint.
In 2003, we achieved our target of reducing global direct GHG emissions by 25% from a base year of 1990. Since 2003, we have further reduced global direct GHG emissions to 36% below 1990 levels.
At the global level, Alcoa Inc has established a Primary Products Greenhouse Network with the mission to reduce our greenhouse footprint worldwide by identifying and accelerating reduction opportunities. Alcoa of Australia is also contributing at the global level as a member of the Australian Aluminium Council and its role in the Asia-Pacific Partnership on Clean Development and Climate.
In Australia our GHG reduction efforts focus on projects, new technology and programs that make significant efficiency gains and reduce both our direct and total GHG intensity per tonne of alumina and aluminium produced.
Alcoa of Australia reports GHG emissions to the Federal Government under the National Greenhouse and Energy Reporting Act, which sets stringent requirements on the reporting of GHG emissions data. PriceWaterhouseCoopers (PWC) has assisted Alcoa with this work and, in addition, PWC conducted a third-party audit of our Australian GHG data in 2009.
Direct GHG emissions are those released directly by Alcoa’s sites, while indirect emissions are those from power stations that supply energy to Alcoa sites. Both direct and indirect emissions are added to calculate total greenhouse gas emissions. Alcoa has been able to make significant efficiency gains in both direct and total emissions per tonne of product (GHG intensity).
Direct Emission Improvements
Since 1990 our Victorian smelters have achieved a direct emissions reduction of 65% per tonne of aluminium produced, our alumina refineries in Western Australia have achieved a direct emissions reduction of over 21% per tonne of alumina, and Alcoa’s rolled products plants in Australia have achieved a direct emissions reduction of 23%.
In 2009 overall direct emissions for the Kwinana, Pinjarra and Wagerup alumina refineries and the Huntly and Willowdale bauxite mines totalled around 4.34 million tonnes of CO2. For our Western Australian operations this equates to a direct emissions intensity of 0.48t CO₂ per tonne of alumina.
Direct emissions from the Portland Aluminium and Point Henry smelters in 2009 were 925,358 tonnes of CO2. This equates to a carbon emissions intensity of 1.80t CO2 per tonne of aluminium.
* Up until 2008, Alcoa used the Primary Products Greenhouse Gas Information System for all its Greenhouse Gas reporting. This Alcoa global system is used for capturing process GHG emissions (such as PFCs) in addition to fuel and energy consumed for calculation of the associated greenhouse gas emissions.
On 1 July 2008, Australia’s National Greenhouse Energy Reporting (NGER) legislation came into effect, requiring mandatory reporting under the NGER System. The first reporting period covered the 2008-09 financial year.
From 2008 onwards our method of reporting in Australia has been aligned with the NGER legislation.
Indirect Emission Improvements
As in previous years most of our emissions in Victoria in 2009 were associated with power generation, either at Alcoa’s Anglesea Power Station or from power purchased from the Victorian grid supply. This represented a total for indirect emissions for smelting of 9.39 million tonnes CO2 in 2009 compared with 9.98 million tonnes CO2 in 2008.
The situation is reversed for the Western Australian refineries. Because the refineries consume natural gas on site to create power and steam, the vast majority of their GHG emissions are counted as direct emissions. Of the total 4.57 million tonnes of CO₂ for WA operations, only around 0.6 million tonnes were indirect emissions.
Total Emission Improvements
We have also reduced our total GHG intensity since 1990. Our Victorian smelters achieved more than a 21% reduction per tonne of aluminium produced, our alumina refineries in Western Australia achieved more than 16% reduction per tonne of alumina, and Alcoa’s rolled products plants in Australia have achieved about a 29% reduction.
The total emissions for WA operations (refining and bauxite mining) in 2009 were 4.57 million tonnes of CO2, with refining accounting for the vast majority of these emissions at an emission intensity of 0.48 tonnes of CO2 per tonne of alumina produced. This represented a milestone where our WA refineries’ carbon emissions intensity fell below 0.5t CO2 per tonne alumina for the first time.
The total emissions for Victorian operations (smelting and power generation) in 2009 were 11.67 million tonnes of CO2, with smelting accounting for the vast majority of these emissions at an emission intensity of 20.10 tonnes of CO2 per tonne of aluminium produced.
Read more about GHG emission reduction under the Air Emissions section - click on the link above left.