This startup is making steel with lasers

Steel is the most widely used metal in the world. You’ll find it in everything from cars to cutlery to skyscrapers. It’s truly a building block for modern society. 



But the way we’ve been making steel for centuries is extremely carbon intensive, accounting for roughly 10% of global carbon dioxide emissions today. That’s because it relies on burning coal to heat iron ore so that it can be transformed into steel. 



In recent years, the industry has pinned its green hopes on a process called direct reduced iron (or DRI) , which swaps out coal for hydrogen or natural gas. This process produces fewer emissions but is more expensive than coal-based steelmaking, and can only be used on about 3% of the world’s ore supply , so it’s hardly the hero the industry needs when steel demand is expected to rise 30% by 2050 . 



“There’s a lot of angst in the steel industry,” says Olivia Dippo, CEO and co-founder of Oakland-based startup Limelight Steel . “The industry is putting out this facade about hydrogen DRI, and then behind the scenes everyone is like, what are we gonna do ? If we’re only feeding 3% of the world’s ore supply to the sustainable method and everything else has to go to the blast furnace which uses coal, then we’re stuck with these emissions.”



From left: Limlelight cofounders CTO Andy Zhao and CEO Olivia Dippo [Photo: Limelight Steel]



A handful of companies are generating innovative solutions. Boston Metal , for example, uses electricity to power its Molten Oxide Electrolysis (MOE) technology that melts iron ore in a carbon-free process. But Dippo has another idea: lasers



Limelight’s technology involves gathering a bunch of small laser diodes together to create an array that, when pointed at iron ore, can melt it in mere seconds. “Normally when people think of lasers, they think of a tiny little spot,” says Dippo. “We’re using lasers differently. We’re creating a big spotlight almost. Everything within that spotlight gets heated up.” Right now, the laser spotlight can cover an area about a foot wide, but Dippo says the plan is to scale up to an area the size of a hot tub, or larger.



If the lasers are powered by clean energy, the whole process results in a 95% emissions reduction compared with the coal-fired steelmaking process. It can be used on any iron ore, and Dippo estimates it will require about 30% less energy than hydrogen DRI. “There’s so much energy consumed in producing the hydrogen that it drives the energy consumption for hydrogen DRI way up,” Dippo says. 



Crucially, Dippo says the company’s models show its process will be more affordable than the blast furnace process once it reaches commercial scale. “I think it’s really important for new sustainable technologies to be cheaper than the fossil-based alternative if possible,” she says. “Steelmaking is a global problem. Actually a lot of steelmaking is happening in developing countries, so in order to have the biggest real global impact on emissions, it’s really important to be cheaper. And that’s the reason we’re really excited about this technology.”



Right now, Limelight is a small startup with eight employees, working in the research and development stage. The company is testing its process inside a small chamber about the size of a microwave. In April it received $2.9 million from the Department of Energy through its Advanced Research Projects Agency-Energy (ARPA-E), which Dippo says will go toward finishing up R&D and building a pilot project next year.