The sole of a new sneaker was once pollution: after carbon dioxide was captured from a power plant or other heavy industry, engineers transformed it to become the building block for a new type of foam.
Called the "Shoe Without A Footprint," the prototype was designed as a demonstration for the Carbon XPrize, which will award $20 million for technology that makes new use of CO2.
"We thought, 'what can we create that is relatable, that can be scalable, that people can touch, feel, see,'" says Gin Kinney, vice president at NRG Energy, which sponsored the XPrize. "We came up with the idea of creating this Shoe Without a Footprint. It's this tangible manifestation of taking this conversion technology and making something simple—everyone owns a pair of sneakers."
Researchers developed five types of foam from CO2 using a proprietary process, which they wouldn't detail to us. "We chose the material with the highest recycled CO2 content relative to the functional criteria needed for a properly engineered shock absorber," says inventor Marcel Botha, CEO of 10XBeta.
With more time, the same process could be used to create the material in the shoe upper as well. Even now, when some of the materials are made with traditional fossil-based ingredients, because the foam in a sole takes of most of a shoe's weight, the total carbon footprint of the prototype is close to nothing—or negative.
Recycled CO2 is already used in some ways in industry. In Iceland, a chemical plant turns carbon dioxide into methanol. In Texas, a startup uses CO2 to make materials used in coatings and adhesives. A Massachusetts company uses CO2 to make polymers. Japanese manufacturers are using it to make polycarbonate, a harder type of plastic.
But many current processes are too expensive to be practical, or use so much energy that they can end up creating more emissions than the CO2 they recycle. The XPrize hopes to spur the development of new carbon conversion technology.
"It also helps turn CO2 into a positively viewed byproduct," says Kinney.
Ultimately, with the right technology, recycled carbon dioxide could be used widely to replace fossil fuels used in chemical manufacturing. "We absolutely do see a future where we can use these technologies at scale," she says.
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