Aluminium industry tackles green issues
THE global aluminium industry has a four-pronged strategy to meet the challenges of greenhouse gas abatement demands.
While the energy required to turn alumina into aluminium accounts for less than 1 per cent of global greenhouse gas emissions, the industry is a high profile target for environmental advocacy. Despite aluminium output having risen 44 per cent since 1990, emissions from the production process have fallen 32 per cent.
The aluminium producers’ strategy for dealing with the global warming issue embraces a further reduction in greenhouse gas emissions, pursuing energy efficiency, maximising recycling and promoting the continuing reduction in the weight of vehicles through use of its metal.
Ron Knapp, executive director of the Australian Aluminium Council, says the local industry is about to produce a sustainability report that will highlight its dealing with environmental impacts of the business.
At Gove in Arnhem Land, one of three regions where bauxite is mined in Australia, the industry, he says, is winning high praise from the area’s traditional owners and from studies of rehabilitation for having regenated more than 2000 ha since mining began in the early 1970s.
Substantial rehabilitation activities are also being pursued in the other two mining areas — the Cape York peninsula in north Queensland and the Darling Ranges in south-west Western Australia. Three years ago Alcoa won the Society of Ecological Restoration International model projects award for successfully returning the botancial richness of jarrah forest in its restored WA mining area.
In the industry’s smelting operations, Knapp points to its success in dealing with perfluorocarbon (PFCs) management. PFCs are a potent greenhouse gas emitted from smelter pots during imbalances in the production process. Substantial reductions have been achieved in PFCs emissions via the improved management of pot bath conditions, he says. The smelters’ PFC emissions in Australia have been cut 90 per cent per tonne of aluminium produced since 1990.
In the alumina refining area, he adds, emission intensity — the amounts of greenhouse gases released per tonne of product — are now more than 20 per cent lower than in 1990 although total emissions are higher because production has risen by 64 per cent in this period.
The alumina/aluminium industry places large emphasis on its recycling capacity. Aluminium products can be used, recycled and re-used almost endlessly,’’ Knapp point out. Nearly three-quarters of the aluminium ever produced globally — more than 700 million tonnes — remains in use today, representing a growing energy and resource bank.’’
Recycling requires as little as 5 per cent of the energy needed for primary aluminium production with a corresponding large reduction in greenhouse gas emissions.
Knapp says the contribution of recycled metal to the global output of aluminium products has risen from 17 per cent in 1960 to 34 per cent today, with 40 per cent targeted to be achieved by 2020.
The international industry reports that it recovers 90 per cent of the metal used for transport and construction applications, and 60 per cent of used drinks cans.
Knapp estimates the consumption of aluminium products in Australia at about 450,000 tonnes a year, but this does not include components contained in manufactured imports, including vehicles. However, when they are scrapped, their metal is added to Australia’s recovery pool.
Energy consumption is the critical commercial and environmental issue for the industry, especially in a country where the dominant source of supply is fossil fuels.
The total amount of electricity consumed by the aluminium smelters is 29,000 gigawatt hours a year — compared to 57,000 GWh used by the entire residential consumption sector of 8.3 million customers — and accounts as much as 30 per cent of its operating costs.
The need to reduce the amount of energy its needs per unit of output is therefore a key focus for the industry as it competes on the global market as well as in terms of reducing its environmental footprint.
Australia,’’ says Knapp, of the world’s lowest energy intensity aluminium industries. While individual state-of-the-art operations recently begun or built overseas are lower in energy intensity, on average the Australian industry performs at least as well as the average for competitor nations.’’