Steel goes into pretty much everything around us – from buildings and bridges to the furniture in our homes. And decarbonizing the steel industry is essential because we need steel to decarbonize the world. Think about it. Solar panels, electric vehicles, even our power grid; steel goes into everything we need to fight climate change.

But there's a problem. Steel manufacturing uses a lot of fossil fuels. It's responsible for 8 percent of global greenhouse gas emissions.

In this episode we break down the race to green, zero-carbon steel. It's a competition among four key technologies: recycling, carbon capture and storage (CCS), electrolysis, and — everyone's current favorite — hydrogen. Or, as we call it in this episode, the Usain Bolt of technology.

Guest Julia Attwood, head of advanced materials at Bloomberg New Energy Finance, profiles each of the competitors in this race and weighs in on which ones are best equipped to clean up the steel industry. We also take a look at how these competitors might actually work together.

Guests: Julia Attwood is head of advanced materials at Bloomberg New Energy Finance. Martin Pei is chief technology officer at the Swedish steel manufacturer SSAB. Usain Bolt was not a guest but makes many cameos on this episode.

The Big Switch is produced by Columbia University's Center on Global Energy Policy in partnership with Post Script Media. This episode was produced by Alexandria Herr and Daniel Woldorff. Theme music and mixing by Sean Marquand. Story editing by Anne Bailey. A special thanks to Natalie Volk, Kirsten Smith and Kyu Lee. Our executive editor is Stephen Lacey.

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