We Need a Green Label for Aluminum

Much depends on where the electricity comes from, but that is not the only factor.

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The Hall Heroult process
The Hall Heroult process.

 Getty Images

If you are buying something made out of wood, it will often have a label on it, usually either FSC or SFI, demonstrating that it met an established forestry standard and was produced sustainably.

There is no labeling system for aluminum, which can be any number of shades of green, depending on how it is made. However, we need one; the carbon footprint of aluminum can vary wildly, and many people are beginning to make purchasing choices based on this. (There is an Aluminum Stewardship Initiative that is discussing this but doesn't appear to have produced one yet.)

But what would a carbon label look like?

Aluminum has been nicknamed solid electricity because of the amount of energy it takes to separate the oxygen from the aluminum in alumina or aluminum oxide (13,500 to 17,000 kWh per ton). Aluminum made with coal-fired electricity has a carbon footprint five times as high as aluminum made with water power. Yet according to Russell Gold in the Wall Street Journal, "there’s no market for low-carbon aluminum, and the provenance of metal is hard to promote. Even when you can certify aluminum is low-carbon, there is no premium for it."

Yet there is an increasing demand for low-carbon aluminum; Apple insists on it and now, Anheuser-Busch has announced that it will use Rio Tinto "low-carbon aluminum made with renewable hydropower along with recycled content" which they say will be "its most sustainable beer can yet, with a potential reduction in carbon emissions of more than 30 percent per can compared to similar cans produced today using traditional manufacturing techniques in North America." This may come as a surprise to some readers who believe that aluminum cans are "green" because they are recyclable, but there is not enough recycled aluminum to go around, so virgin aluminum is required. "Currently, around 70 percent of the aluminum in Anheuser-Busch’s cans is recycled content."

This should be an eye-opener: even the most basic aluminum product, a beer can, has virgin aluminum in it, and all virgin aluminum has a carbon footprint, it is all a matter of degree, so our hypothetical label will have to cover a range of colors; we will start with Dark Brown and go through to Dark Green.

There Is No Such Thing As Carbon-Free Aluminum

mining bauxite
Mining Bauxite. Getty Images 

Let's get this out of the way first; last year there were lots of headlines saying things like Apple buys first-ever carbon-free aluminum. But it is still made from bauxite, which is crushed and cooked in caustic soda to separate out the alumina hydrate, which is cooked at 2,000°F to drive off the water, leaving anhydrous alumina crystals. According to the Financial Review, "It takes about 2.5 megawatt-hours of electricity to make one tonne of alumina and a lot of the world’s best refineries draw that power from gas generators." So even the greenest virgin aluminum has a carbon footprint. [More: What's Alumina? It Is the Stuff That Aluminum Is Made Of, and Making It Is a Problem]

Dark Brown Aluminum

Baotou Coal Power Plant
Baotou Coal Power Plant.  Ryan Pyle/Corbis via Getty Images

This is aluminum made with coal-fired electricity, as is done in China, Australia, and the U.S., with a carbon footprint of about 18 tonnes of CO2 per tonne of aluminum. Because of cheap coal, China broke production records in 2019 and prior to the pandemic crisis had 56% of the market. According to Christopher Clemence of Aluminium Insider, the aluminum smelters have captive coal-fired generating plants that are "granted a legal protection from the country’s environmental regulation regime." This is a serious problem in the fight against climate change:

"China’s actions (or rather inactions) vis-à-vis coal-fired power in the production of aluminium become even more galling in comparison with aluminium’s positive contributions elsewhere on Earth. Simply put, China’s insistence upon producing one of the most important materials for battling carbon use via carbon-intensive means is a stunning perversion of aluminium’s promise."

Light Brown Aluminum

Aluminum cans
CC BY 2.0. Lloyd Alter

Aluminum smelters have been built in Saudi Arabia that run on natural gas, "part of the kingdom’s Vision 2030, which is a plan to diversify its economy and make it less reliant on the ever more volatile global petroleum trade." It has a carbon footprint of about 8 tonnes of CO2 per tonne of aluminum. 362,000 tonnes of can sheet was imported from Saudi Arabia last year because there was not enough recycled aluminum on the market for the can makers. As we noted earlier,

"So everyone who feels OK drinking their beer and pop out of aluminum cans because 'hey, they're recycled' should realize that they are not, there is more money in cars so nobody is bothering, and they are just going to waste. Meanwhile, the can sheet is coming from ... Saudi Arabia?"

Light Blue Aluminum

Bonneville Dam
Bonneville Dam.  Public Domain

Many people call aluminum made with hydroelectricity green, but blue might be a better color since that's the color of water and we have to leave something for recycled aluminum. It used to be made this way in the USA, but TVA and Columbia River power got too expensive and the companies moved offshore. Now the big suppliers are Russia, Norway, Iceland, and Canada. 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."

But even hydro-powered aluminum has a carbon footprint of about 4 tonnes of CO2 per tonne of aluminum because the smelters use the Hall-Héroult process, where carbon anodes are consumed when the carbon reacts with the oxygen in the alumina to make CO2. It's in the chemistry as well as in the electricity.

Dark Blue Aluminum

Elysis Aluminum ingots
Promo image. Elysis 

This is new, and a huge advance. The Elysis process gets rid of the carbon anodes and replaces them with some kind of proprietary material. According to Aluminum Insider, it is "a ceramic anode for aluminium production that emits only oxygen and no greenhouse gases, and last 30 times longer than those made from conventional materials." 

Apple has invested in it, along with the Canadian government; according to Apple, they "learned that Alcoa had designed a completely new process that replaces that carbon with an advanced conductive material, and instead of carbon dioxide, it releases oxygen." Apple has taken delivery of its first batch, although that was made in Pittsburgh with dirty power. It is being touted as carbon-free, but again, if it is made from alumina then it cannot be truly carbon-free.

Light Green Aluminum: Recycled From Pre-Consumer Waste

Apple Macbook Air Launch
Video screen capture. Screen capture/ Apple Macbook Air Launch

The crowd went wild when Laura Legros announced that the new Macbook Air would be made of 100% recycled aluminum. But what they are doing is collecting all the swarf from machining out the cases with a CNC machine; they could have cast the cases and had no waste at all, but they probably wouldn't be as thin and light. As we have noted many times, "having lots of pre-consumer waste means that you are probably doing something wrong" in your manufacturing processes; it is not a badge of honor. As Matt Hickman noted in Treehugger, "Some would say that pre-consumer recycled content isn’t even truly recycled at all because the waste involved isn’t even truly waste, if you get my drift."

Dark Green Aluminum: Recycled from Post-Consumer Waste

Scrap Aluminum
 Photo by Mediacolors/Construction Photography/Avalon/Getty Images

When you come right down to it, the only truly green aluminum is recycled from post-consumer waste. This is where we truly have to go, to a closed-loop where we stop the hugely destructive mining of bauxite and processing it into alumina. The recycling rate of aluminum is high at 67% but the rate for packaging is far lower at 37%. Much of that goes into foil pouches and multilayer materials that can't be recycled affordably. That's why we have to design for deconstruction and disassembly so that materials can be recovered easily and avoid what Bill McDonough called "monstrous hybrids" that can't be taken apart.

As Carl A. Zimrig noted in his book "Aluminum Upcycled: Sustainable Design in Historical Perspective," we have to do a lot more than just recycling, and we have to look at what we truly need.

"The most sustainable automobile design of the twenty-first century is not the F150 aluminum pickup, or the electric Tesla, the most sustainable automotive design is not an automobile at all, but a system to distribute transportation services – car sharing, bicycle sharing, product service systems, simply owning less stuff and sharing more so that overall demand for new stuff declines. Because even such intense and virtuous recycling that we do with aluminum, even if we catch every single can and aluminum foil container, it’s not enough. We still have to use less of the stuff if we are going to stop the environmental destruction and pollution that making virgin aluminum causes."

I suspect that we are going to be voices in the wilderness here and that those water-powered carbon-lite aluminums are going to be called green. But really when you get right down to it, the only truly green aluminum is recycled, and we don't have enough of it to keep living this kind of lifestyle of consuming ever more stuff.