Huge aluminum demand expected in solar industry, concerns arise on emissions

Owing to its high conductivity, low weight and excellent corrosion resistance, aluminium is one of the key raw materials in the solar industry used in cells, module frames, mountings and inverters. While abundant and cheap, the primary production of aluminium comes at a high cost in terms of energy and associated greenhouse gas emissions, which will need to be taken into consideration if we are  to rapidly reduce emissions to ‘net zero’ and limit global warming to less than 2 degrees Celsius.

A group of researchers at the University of New South Wales (UNSW) have sounded the alarm bell about the climate pressure aluminium could create if we were to solely rely on primary production by 2050. They found that the growth to 60TW of PV, envisaged by the broad electrification scenarios of recent photovoltaic roadmaps, could require up to 486 MT of aluminium by 2050. This enormous manufacturing task could in turn undermine PV’s green credentials due to its large global warming potential.

“If the emissions intensity of the primary production process is not reduced, then more than 3000 Mt CO2e could be released in the atmosphere,” researcher Alison Lennon, told pv magazine. “However, if we can decarbonise the electricity used to smelt aluminium, utilize as much secondary aluminium as possible and collect and re-use aluminium from old modules, then we can significantly curtail this global warming.”

Namely, to have more than 60TW of PV installed by 2050, up from just over 700GWp at the end of 2020, we would need to produce up to 4.5TW of additional capacity each year. The researchers modelled different primary production emissions reduction scenarios to 2050 targets of 1.5 (base scenario), 3.5, 5.5 and 7.5 t CO2e t aluminium and compared this to the worst case scenario in which the emissions intensity is unchanged from the 2020 levels with a primary production emissions intensity of 14.5 tones of carbon dioxide for each tone of aluminium produced.

They considered process improvements directed at reducing direct emissions, potential alternatives to aluminium and the use of recycled content in the aluminium as the most efficient way to reducing the material’s global warming potential. They reminded that aluminium is attractive to recycle because its secondary production requires only around 5% of the energy required for primary production and generates just 3–5% of the emissions from primary production. In their analysis, the percentage of recycled content in the aluminium used for the added capacity was assumed to linearly increase from 34% in 2020 to 75% in 2050.

Finally, the researchers underlined that efforts to reduce the environmental footprint of aluminium production need to happen within the next 10 years to provide the best opportunity of keeping emissions to below 1,000 Mt of CO2 equivalent by 2050. Their research was published in the journal Nature Sustainability.