An energy company just debuted a shoe made from power plant emissions

A new sneaker made of recycled carbon dioxide barely leaves a footprint - on the environment, that is.

Energy company NRG has debuted a shoe with a primary material that incorporates gaseous waste, or effluent, emitted by power plants. To make the sneaker, the effluent is captured and cooled, and the CO2 in it is separated out. That substance then becomes the base of a chemical that's used to create the polymer (or plastic) that forms the shoe's supportive foam.

NRG has declined to reveal how that polymer is made, calling the process proprietary. But Marcel Botha, CEO of 10xBeta, the company that created the sneaker, says the CO2 foam makes up approximately 75% of the shoe. The rest of the materials aren't made of recycled CO2, but the emissions released during their production could be captured via the same processes that collect the carbon dioxide used to make the shoe.

The "Shoe Without A Footprint" is a prototype NRG created as a demonstration of what could come out of the four-year Carbon XPrize competition, which the company sponsors.

"The Carbon XPrize is all about turning CO2 into products that people would use everyday," Paul Bunje, XPrize's principal scientist, tells Business Insider. "NRG wanted to show some leadership by manifesting what we're talking about."

The competition, launched in September 2015, asks teams to submit technical and business proposals for ways to capture CO2 and convert it into useful materials. Of the 47 entries received, 10 finalists will be chosen to spend two years building and testing their product. The top teams will eventually receive a share of the $20 million grand prize.

NRG currently has no plans yet to manufacture the shoes for public sale - there are only about five pairs in existence. But the company hopes the example can inform similar projects in the competition that will actually make it to market. The initial round of XPrize proposals included plans to turn carbon into cement, plastics, fuels, agricultural products and even space-age materials, Bunje says.

Of course, energy companies like NRG have an obvious incentive to encourage innovations that capture carbon dioxide and transform it into everyday products, since that could alleviate some of the nastier effects of the fossil fuels industry. But it's a worthy goal nonetheless.