Why Trump's 25% tariff on aluminum will lead to a big burp in greenhouse gas emissions

Oh, and cars, beer and soda pop will be a lot more expensive.

How they used to make aluminum in the USA

The President of the United States recently announced new tariffs on imported metals. “Any steel coming into the United States is going to have a 25 percent tariff,” Trump told reporters aboard Air Force One on Sunday. “Aluminum, too.”

Currently about 2/3 of primary aluminum comes from Canada, which the Aluminum Association calls “the indispensable trading partner.” The reason is that Canada has lots of cheap hydroelectric power in British Columbia and Québec. Aluminum has been described as “solid electricity” because it takes 13,500 to 17,000 kWh to make a ton of it. The Bonneville Power to make a town of it.

The USA used to have lots of cheap hydro power. The Bonneville and Grand Coulee dams were built by Franklin Roosevelt to create jobs during the depression, but the most important jobs they created were at Boeing and Douglas, who needed the aluminum for airplanes. From an earlier post in my archives:

But while the population grew over the last 75 years, the number of dams cannot grow very much. The price of electricity kept rising to the point where making aluminum in the USA simply isn't economically viable; as Ana Swanson noted in the Washington Post, "In Washington state, for instance, the smelters that used to operate near the hydroelectric power plants along the Columbia River have been priced out by the power-chugging server farms of tech companies such as Microsoft." So the companies moved their smelting to where power is cheap; to Iceland, which has lots of power and few people, and to Canada, where the aluminum companies actually built dams and the power plants for their own use. American aluminum production dropped by three-quarters over the last few decades, squeezed by expensive electricity and cheaper coal-fired Chinese aluminum.

At the time, the aluminum companies were looking for cheap power, but there was another benefit that became important: There no carbon emissions from generating the electricity that powered the smelters. Companies which wanted to reduce their carbon footprint would give priority to hydro-powered aluminum. It’s all in the chemistry; let’s step back and look at how aluminum is made:

Aluminum starts with bauxite, a red ore that is strip-mined in Jamaica, Guinea, Russia, Malaysia and Australia as well as Brazil. It is processed on site to separate out alumina, or aluminum oxide. The bond between the oxygen and aluminum is tight; in the Hall-Heroult process, the alumina is dissolved in cryolite, a mineral made of sodium aluminum fluoride that was found in Ivittuut, Greenland, and now synthesized. This mixture is zapped with an average of 13,496 kWh per tonne of aluminum, which causes the aluminum to sink to the bottom and the oxygen to bond with the carbon in the anode, creating carbon dioxide at a rate of 4 tonnes of CO2 for every tonne of aluminum.

That’s still a lot of CO2, so companies like Apple invested in a new process developed by Rio Tinto that uses an inert anode that doesn’t get eaten up to make CO2. Tim Cook and Justin Trudeau are celebrating the Elysis aluminum that is produced with Québec hydro power.

In an earlier post, What colour is your aluminum? It makes a massive difference, I categorized aluminum by the carbon emissions produced from the mining of bauxite to the final product. The biggest winner the last time tariffs were stuck on aluminum was Century Aluminum in Kentucky, which is coal-fired. Going from light blue Canadian aluminum to brown American aluminum means carbon dioxide emissions increase by 4.5 times. But carbon emissions are just the start.

As Phil McKenna of Inside Climate News explains much better than I can, there is an “anode effect” where, if the levels of alumina drop too low, flourine released from the cryolite reacts with the carbon in the anodes to make perfluorocarbons, which have global warming potentials (GWP) of between 7380 and 12,400 times that of CO2. McKenna writes:

“In 2021, the Sebree plant, the largest U.S. aluminum production facility operating at full capacity, vented 24 tons of perfluorocarbons (PFCs) into the air. The emissions equal the annual greenhouse gas emissions of 40,000 automobiles—ones that will remain on the theoretical road for tens of thousands of years. Meanwhile, a newer plant also owned and operated by Century Aluminum in Grundartangi, Iceland, emits just one sixth the perfluorocarbons (PFC) emissions per ton of aluminum, as compared to the company’s Sebree plant. It’s a tale of two smelters: older U.S. plants with some of the highest PFC emissions rates in the world and their overseas counterparts with far lower emissions — even when operated by the same multinational companies.”

Borders didn’t previously matter with aluminum. The Aluminum Company of America even owns 40% of the McCormick generating station in Québec. But the American president would rather burn more coal and saddle his citizens with more expensive aluminum producing more CO2 and more perfluorocarbons.

It won’t bother Apple, because the aluminum is such a small part of its costs, but the price of an F-150 pickup truck just went up; there’s not enough American aluminum for all the cars and trucks that use it. Airbus just got a nice gift as Boeing is now paying more. And your next can of beer will be a bit more expensive because there is going to be even more competition for recycled aluminum. You all know who to thank.