Behind the Shining: Aluminum’s Dark Side
Carbon dioxide
The industry emits carbon dioxide at each stage of production, from the
mining and processing of bauxite, to the electrolytic refining of alumina,
and the casting of aluminum.
A quintet of Massachusetts Institute of Technology scientists, led by
Jochen Harnish, in a 1999 study titled “Primary Aluminum Production:
Climate Policy, Emissions, and Costs,” found that “the source of electric
energy used for the electrolytic reduction is the single most important
factor influencing total carbon dioxide emissions from primary aluminum
production. The specific emissions of CO-2 vary by a factor of five
depending on whether coal or hydroelectricity is used as a source of power
for the reduction cells.” (Jochen Harnisch, Ian Sue Wing, Henry Jacoby,
Ronald Prins, “Primary aluminium production: climate policy, emissions and
costs,” paper presented at the Kyoto and Montreal Protocols’ Joint Expert
Meeting, Petten, May 1999)
Another study has calculated that the aluminum production cycle, including
mining, processing, refining, and casting, produces about 12 tons of carbon
dioxide per ton of aluminum produced. (R. Huglen and H. Kvande, “Global
considerations of aluminium electrolysis on energy and the environment,
Light Metals 1994, pp. 373-380)
The industry’s International Aluminium Institute has lower carbon dioxide
estimates of 7.4 tons of carbon dioxide per ton of aluminum production
(including 5.8 tons from energy and 1.6 from the electrolytic process).
(IAI, “Aluminium’s Life Cycle,” on website world-aluminium.org, 2000)
The MIT study predicts that CO-2 emissions from the industry will rise from
about 2 billion tons in 1985 to about 3 billion tons in the year 2030. The
more coal that is consumed to power new capacity, the more emissions will
occur. If 75% of new capacity is fueled by coal, then the amount of CO-2
generated per ton of aluminum cast would increase from 12 to 18.3 tons.
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