rethink those aluminium cans

[Guest guest]

An environment blog from Tuesday, May 08, 2007

Fred's footprint: A can-load of energy

I wanted to find out where the aluminium in my beer can came from. And

I ended up in Gladstone in Queensland, Australia, one of the

greenhouse-gas emissions hubs of the world.

 

Smelting aluminium is one of the most energy-hungry industrial

activities on the planet. It uses 2% of the world's electricity. In

Gladstone, one of the world's biggest mining companies extracts the

metal from the ore bauxite. This is mined across the state at Weipa,

where 10% of the world's bauxite is stripped from land that used to be

native bush.

 

Most aluminium smelters use hydroelectricity. But Rio Tinto gets its

power from a 30-year-old power station in the town that burns cheap

Queensland coal.

 

In Gladstone, the bauxite arrives by barges which thread their way

around the Great Barrier Reef. First it is refined into aluminium

oxide - alumina. Then the alumina goes to one of three giant smelting

halls, each 900 metres long.

 

Stepping into an aluminium smelter is like going back to an earlier

industrial era. " The Hall-Herout smelting process is virtually

unchanged since it was invented in the 1880s, " production manager Alan

Milne told me.

 

The process heats the alumina to almost 1000° C and then subjects it

to an immense electric current delivered through thousands of carbon

anodes, each weighing more than one tonne.

 

The current strips the oxygen from the alumina and combines it with

the carbon from the anodes. Result: pure aluminium ingots and a great

deal of carbon dioxide gas.

 

Combining the CO2 emissions from the smelting and the 900 megawatts of

coal-fired power needed to sustain the process, you get 17 tonnes of

CO2 for every tonne of aluminium. That's 270 grammes of CO2 per

aluminium drinks can.

 

Gladstone makes enough aluminium for almost 40 billion cans a year -

six for every person on the planet. In doing that, it emits 10 million

tonnes of CO2 a year - as much as a typical European city of one

million people.

 

Besides using one-fifth of the Queensland state's electricity, around

the world, Rio Tinto smelters use one-sixth of New Zealand's power, a

quarter of Tasmania's and a tenth of Wales's.

 

Not surprisingly, Rio Tinto is growing worried about its CO2

emissions. They don't fit well with its new environmentally- and

socially-aware image. And even though Australia is currently a Kyoto

refusenik, the company reckons the government will soon sign up to

future emissions reduction targets.

 

So what is it doing? Last year it announced plans to build a new

smelter in Abu Dhabi, powered by natural gas. Rio Tinto is not alone.

As its managing director pointed out: " The Middle East is fast

becoming a key region in the global aluminium smelting business. "

 

Why so? It's a no-brainer. As the company's head of climate change

told me when I asked about the new geography of aluminium smelting:

" Abu Dhabi is outside the Kyoto protocol. " It has no emissions

targets. Silly me.

 

But don't despair. There could be salvation for the aluminium

business. Its green credentials are not as bogus as you might imagine.

Guess why. Answer in my next blog in a fortnight.

 

Fred Pearce, senior environment correspondent

 

 

" Every gun that is made, every warship launched, every rocket fired, signifies

in the final sense a theft from those who hunger and are not fed, those who are

cold and are not clothed. "

-- Dwight Eisenhower