Green smelting – a road to the future?
With 2021 shaping up to be the year the world got serious about decarbonisation, every sector can expect to come under the climate change microscope. The vast carbon emissions from steel and aluminium production often overshadow the environmental impact of zinc, lead and copper smelting. But the energy-intensive process of producing these metals is far from squeaky clean. So, is ‘green’ smelting possible, and what are the obstacles to making it happen?
Smelting of zinc, copper and lead produced a combined 53 million tonnes of carbon dioxide equivalent (MtCO2e) in 2020. We forecast that from 2020 to 2040, zinc production will increase by over 30%, lead by over 40% and copper by more than 45%. If there is no change in the core technologies or power sources used to produce these metals, a total of 1,008 MtCO2e will be emitted over the next 20 years.
In the face of increased scrutiny, continuing to play by current environmental rules is not an option for smelters. A proactive approach to decarbonising production is needed.
GREEN SMELTING: IS IT POSSIBLE?
Renewable energy was already used to smelt 40% of zinc and 32% of lead produced in 2020 – and that can be scaled up. But can it hit 100%? Based on our review of the power mix of the top 10 copper, zinc and lead producing countries, it’s unlikely. Smelters in these countries cannot get 100% of their power need via the grid from renewable sources, now or even in the future.
As things stand, by 2040 over 90% of zinc production will still come from smelters that draw only 30-60% of their grid power from renewable sources. For copper and lead the outlook is even worse.
One solution is to build new and replacement smelting capacity close to existing or planned sources of renewable power. Another is for smelters to build dedicated solar or wind installations to serve their facilities, either on their own or in partnership with renewable energy providers.
