Global transport, packaging and construction sectors will have to brace for more shortages in aluminium as China’s power-intensive metals industry buckles under the pressure of a national power crisis while Beijing maintains a cap on smelting to meet emissions targets.

Alongside curtailed magnesium output – another power-intensive metal – aluminium production in China has suffered a 2.3 million tonne drop since the onset of the power crunch in September, when widespread power rationing swept the country amid a race to cut down on carbon emissions and reduce power generation.

The price soared to a 13-year high of US$3,000 a tonne in October, the highest mark since 2008. Before reaching that milestone, aluminium was generally priced in the range of US$1,500 to US$2,000 a tonne. It cooled to about US$2,700 a tonne on Friday.

The hit to the world’s biggest aluminium supplier’s output was not an overnight phenomenon and has been sliding since China’s power woes began to rear their head late last year. While China is no stranger to blackouts during peak power-usage seasons, power consumption last winter exceeded that of the summer months for the first time in about 10 years. More than a dozen cities across various provinces set caps on electricity usage for factories.

Those blackouts continued periodically through the year, until September when power rationing measures were imposed in more than half of China’s provinces.