These New Lego Pieces Are Made of Sustainable Plastics

General Tech


Three years ago, Lego pumped $155 million into a new Sustainable Materials Center, which set more than 100 employees on the task of Lego using fully sustainable materials in its products by 2030. This month, the company showed off the first brick-based fruits of those efforts: About 25 different Lego shapes, many of them plants, will now be made from sugarcane-based polyethylene rather than oil-based plastic. It’s an important milestone, but a relatively small one—which no one knows better than Lego itself.

By the end of the year, under two percent of Lego bricks will use the new polyethylene, a haul that includes not just bushes and trees but also the brushes in the car washes and street sweepers in the Lego City line, and at least one set of dragon wings. While the percentage sounds small, keep in mind that Lego sells 75 billion elements every year. Little pieces add up quick.

About 25 different Lego shapes, many of them plants, will now be made from sugarcane-based polyethylene rather than oil-based plastic.

But other numbers come to mind that may help put Lego’s long-term sustainability challenge into even sharper perspective. The company makes more than 3,700 individual elements. It uses 20 different kinds of plastic to make those bricks, tires, and adorable minifig helmets. And as many as 80 percent of Lego pieces consist of acrylonitrile-butadiene-styrene, or ABS, a petroleum-based substance that polyethelene can’t hope to replace. In fact, it’s still unclear if anything can.

If anyone knows how to methodically piece together a solution from a range of disparate parts, though … well, you get it.

Plant Matters

Let’s start with the good news. Those bushes and trees really are a big deal. It took about two years for Lego to settle on the sustainable polyethylene that goes into them, which uses ethanol produced from sugarcane rather than petroleum. That time was spent sourcing, testing, and perhaps most importantly figuring out how to produce the bricks in quantity.

All that work goes toward not improving on existing oil-based elements, but precisely replicating them.

“You never notice the difference. That is what our fans, young and old, are obviously concerned about as well,” says Tim Brooks, a Lego vice president who heads up environmental responsibility efforts. “In this occasion, what we’ve produced has exactly the same durability, quality, and safety as we have today.”

As far as replacements go, though, it’s low-hanging fruit, which Lego readily acknowledges. Plant-based polyethylene won’t be invading any of Lego’s load-bearing elements; you don’t stack trees or dragon wings. All it needs to do, really, is stand there and look pretty. “It’s much softer, it has more of a matte finish, it’s more flexible, it doesn’t require that very tight tolerance that a brick does to stick together,” says Brooks.

Another obvious but potentially undersold benefit of bio-polyethylene? It already exists.

“This is good for the short term, because they’re using materials that are available now,” says Gihan Hewage, who follows bio-based materials and chemicals at Lux Research. “This is a very isolated step in the grand scheme of what they’re doing.”

Even the production process, Hewage says, should transition smoothly. Aside from a higher materials bill, the polyethylene swap won’t cause much of a hassle.

So! One oil-based plastic down, just 19 to go. Except, as you may have guessed, it’s not quite so simple.

The ABS Blues

It’s important to note that exact bioplastic replacements for the majority of Lego’s remaining stock do not exist. Not yet, anyway, and those materials are certainly not available at a scale that can produce tens of billions of precisely fitting shapes each year.

Indeed, Lego can’t reach its 2030 goal without solving ABS, a material that affords the company the attributes it so prizes: Durability, color fastness, strength, and clutch power, or how well two joined bricks stay together. Plenty of plant-based plastics exist, but none checks all of those boxes.

“We’ve had 50 years to play with ABS and perfect it,” says Brooks. “We’re not at that stage with bio-based materials and recyclable materials. How do you control the shrinkage in the mold? How do you control processing the material? The colors?”

It’s not for lack of trying. The prototype bricks are made from a sustainable plastic—Lego wouldn’t specify which—but Brooks says that while they look fine in pictures, they suffer from marbling of color, and lack the precise clutch power that keeps Lego builds together.

An Italian company called Bio-On, meanwhile, makes Lego knockoffs out of polyhydroxyalkanoates, or PHA, a polymer developed from a bacterial strain. They look like Lego, and stack like Lego, but in the long term, Hewage says, they don’t act like Lego. And that’s what matters.

“They developed a product on a smaller scale,” he says. “They have the ability to make something that looks like a Lego. The challenge is, it’s almost definitely not going to have the requirements Lego has for materials, no matter how they process it.”

A potentially more promising alternative may be ABL, recently developed at Oak Ridge National Laboratory in Tennessee. ABL uses the same acrylonitrile and butadiene as ABS, but swaps in lignin, a biological material, for the latter’s petroleum-derived styrene.

“A variant of ABL could be a solution,” says ABL co-inventor Amit Naskar, who does also note that ABL currently isn’t a perfect one-for-one ABS replacement; it’s not as hard, and it has more stretch. “Or maybe it’s a different kind of renewable. There are scientists all over the world working on renewable material.” Surely one of them will suit Lego’s needs.

To do so—and yes, it just keeps getting harder—they’ll have to also come up with a polymer that, as polyethylene likely does, suits Lego’s existing production process.

“That’s the secret sauce. A lot of it is how we make the bricks, how we optimize the machines,” says Brooks. “Different materials perform in different ways. Some materials are hydroscopic and some are hydrophobic. Some are dusty and some are not dusty. Some have high static and some have low static. Some can be blown through tubes, some have to be screw-fed. There are a lot of different considerations.”

2030 or Bust

Lego has, by its self-imposed deadline, 12 more years to figure out how utilize sustainable materials to make the remaining 98 percent of its plastic elements. As you’ve likely gathered by now, that’s a daunting target. It’s not, though, impossible. Here’s how the company might get there.

Start with what’s already done: those bio-polyethylene pieces. More expensive for Lego, maybe, and not something that can translate across the rest of the line, but you’ve got to start somewhere. (There’s also a question of how much more sustainable bio-polyethylene is, really, given the energy-intensive process required to produce it, but let’s set that aside for now.)

Next up: Those 19 other types of plastic that comprise the rest of the line. Importantly, Lego won’t necessarily need to find 19 perfect one-for-one replacements.

“We might end up with more, we might end up with less,” says Brooks. “Some materials that we find might perform the function of several that we have today, or it might be the reverse. The function that we get from one material, depending on its application and its shape, might need several materials.”

All of those conditionals, again, stem from the fact that these materials don’t yet exist, at least not in quantity, and even 2030 might not be a long enough timeline to find and mass-produce them.

“Even 12 years from now, they might be able to make every single one of their bricks from plants in the lab at a small scale, but having every single one of their bricks sold in stores, it’s going to be really tough,” says Hewage, the bio-chemicals researcher.

But maybe they don’t have to. Lego also counts recycled plastic—not actual Lego bricks, which tend to get passed down along generations, but ABS plastic generally—as a sustainable source. Using recycled material has its own challenges, particularly around quality control and color reproduction. But the combination of developing just enough bio-based polymers, and sourcing just enough high-quality, recycled ABS, could be enough to get Lego across the finish line.

“Some bricks will be recycled material, some bricks will be bio-based,” says Brooks. “That’s probably where we net out.”

Others take an even more optimistic view. “If they’re targeting 2030, it’s certainly doable,” says Oak Ridge’s Naskar.

There’s too much work being done in this space, he suggests, for something not to click.


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