The news must have put a smile on the faces of New York-based Alcoa executives who had been considering cutting output in Brazil, according to a report by Bloomberg.

Brazilian president Dilma Rousseff wants rates to be cut by 28% in order to boost growth in the South American country.

While metal producers are the big winners, Brazilian power companies found $6.4 billion wiped off their market value.

The biggest winners, of course, are aluminium producers. Don't forget that power accounts for 40% of smelter production costs.

In fact, Klaus Kleinfeld, CEO of Alcoa, had a go at the Brazilians earlier in the year, blasting them for their 'unbelievably high' power costs.

Perhaps Rousseff was listening.

A 28% cut in electricity rates, claims Bloomberg, will mean a reduction in average fixed costs for Brazilian materials manufacturers of 4%.