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Greenhouse Challenge
Reducing Emissions
This was achieved through reductions in perfluorocarbon emissions, gas consumption, electricity usage and carbon usage per tonne of metal produced.
Alumina refining also produces substantial amounts of greenhouse gas. During the 1980s, converting our energy supply from imported fuel oil to local natural gas, and the commissioning of new facilities, reduced refinery greenhouse gas emissions in Western Australia by 18.6 percent per tonne of alumina.
Further modest gains have been achieved through the 1990s from additional energy efficiency and process improvements.
In 1996, with the other members of the Australian Aluminium Council that operate aluminium smelters, we joined the Australian Government's Greenhouse Challenge program. Alumina refiners joined from 1997.
Life Cycle
The amount of greenhouse gas produced during refining and smelting is only part of the story. Life cycle assessment is an emerging tool for evaluating the total environmental impact of a product.
Aluminium use in transport is a good example. Substituting aluminium for traditional higher-density materials used in vehicle manufacture reduces overall weight, and hence fuel consumption. Net savings over the typical life of a vehicle can be as high as 20 kilograms of greenhouse gas for each kilogram of aluminium used.
Remelting aluminium scrap saves up to 95 percent of the greenhouse gas emissions associated with primary aluminium smelting. The recycle rate for automotive scrap is close to 90 percent. Recycled aluminium now makes up more than 60 percent of aluminium used in new vehicles, and is expected to increase further.
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