Clean energy journalism for a cooler tomorrow

Chart: Aluminum has a big CO2 problem. Here’s how to clean it up

To hit global climate goals, carbon emissions from aluminum production have to drop 92 percent by 2050. Step one? Building a ton of clean energy.
By Carrie Klein

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Pots and pans, soda cans, skyscrapers, laptops, even solar panels — all these things share a common ingredient in aluminum. The material is ubiquitous and useful, but the process of making and recycling it is a major source of planet-warming pollution.

By 2050, aluminum producers in North America will need to cut carbon emissions by 92 percent compared to 2021 levels to meet net zero goals. A recent report from the Aluminum Association shows the solutions that could help the industry get there.

The bulk of aluminum industry emissions comes from the massive amounts of electricity used to power giant smelters. While some North American facilities use hydropower, most rely on electricity generated by fossil fuels. Reducing the use of dirty electricity will require ramping up renewable sources on the energy grid — something that is happening fast, but not fast enough to be on track for the Biden administration’s goal of a 100 percent carbon-free grid by 2035.

The next biggest contributor to aluminum emissions is the use of fossil gas to fire furnaces for recycling aluminum, which makes up 75% of the U.S.’s aluminum production. Electrifying those furnaces or swapping in cleaner fuels would slash carbon emissions by 23 percent. The tech is in the early stages, but one company, Norway-based Hydro, successfully produced a batch of recycled aluminum last year using green hydrogen at its facility in Spain and is testing direct electrification in Norway.

Another chunk of emissions comes from the carbon-intensive process of making primary aluminum. There are two key steps with room for improvement, and cleaning up both could cut aluminum emissions by 32 percent.

First is the extraction of the element alumina from a rock called bauxite — a high-heat process that currently relies mostly on coal and fossil gas. Some companies are exploring how to replace fossil fuels with cleaner fuels, like green hydrogen.

In the second step, alumina is turned into aluminum. To do that, facilities use what’s called a carbon anode, which releases CO2 directly in the process. Several companies, like Elysis and En+ Group, are working on alternative anode technologies that would release only oxygen as a byproduct — not CO2.

But many of these new anode technologies likely won’t become realistically applicable” until the early 2030s, said Annie Sartor, the aluminum campaign director at Industrious Labs.

Though some of the solutions are still coming into focus, the U.S. could soon see its first real-world attempt to decarbonize primary aluminum. Century Aluminum Company has been selected to negotiate up to a $500 million government award to build a smelter in Kentucky that can run on 100 percent clean energy. But to truly decarbonize, the company will need to figure out how to pull the biggest lever for reducing aluminum emissions — grid decarbonization — in a state that has relatively little clean energy to speak of.

Carrie Klein is an editorial intern at Canary Media.