(CNN) The US Department of Energy is announcing a massive investment in direct air carbon removal projects, in hopes of kickstarting an industry that energy experts say is critical to getting the country's planet-warming emissions under control.
Direct air carbon removal projects are like giant vacuum cleaners that suck planet-warming carbon dioxide out of the air and lock it away. They use chemicals to remove the gas from the air and store it in rocks deep underground or put it to use in materials like concrete.
Nature can do this on its own -- forests, bogs and oceans all suck carbon out of the atmosphere -- but not nearly fast enough to keep pace with human fossil fuel emissions. Experts tell CNN these giant, carbon-removing machines are the next frontier to bring CO2 levels down.
The Department of Energy on Thursday is releasing a notice of intent for developers for four direct air capture hubs -- each capable of removing over a million tons of CO2 per year -- using $3.5 billion from the bipartisan infrastructure law. Removing 1 million tons of CO2 per year is equivalent to taking around 200,000 gas-powered cars off the road.
"The UN's latest climate report made clear that removing legacy carbon pollution from the air through direct air capture and safely storing it is an essential weapon in our fight against the climate crisis," Secretary of Energy Jennifer Granholm said in a statement. Granholm said the infrastructure law funding "will not only make our carbon-free future a reality but will help position the U.S. as a net-zero leader."
Department officials say the notice, which was shared first with CNN, is a crucial step in building this industry in the US.
"For us to get to millions of tons [removed from the air] per year through these demonstrations will be critical," said Jen Wilcox, principal deputy assistant secretary in DOE's Office of Fossil Energy and Carbon Management.
President Joe Biden is targeting net-zero carbon emissions in the US by 2050, but experts say that isn't achievable by simply transitioning from fossil fuel energy to renewables -- the country must also actively remove carbon dioxide from the atmosphere because of how much it has already emitted.
Direct air removal "is a suite of tech and strategies to get to this multi-gigaton carbon removal scale we need to get to in roughly 25-30 years," said John Larsen, a partner at the nonpartisan firm Rhodium Group.
The US needs to decarbonize and to dramatically scale up direct air removal, Larsen said, to the point that these machines can remove not millions but billions of tons of CO2 per year. A billion tons of CO2 removed in a year would be equivalent to taking over 215 million vehicles off the road.
Climeworks' direct air removal project in Iceland is the largest, according to the company, removing about 10 metric tons of CO2 every day -- about the same amount of carbon that 500 trees could remove in a year.
The US hubs envisioned by DOE will be much larger. Humans have not yet built a megaton-sized direct air removal system, Larsen said, and DOE's hubs are an important first step to both dramatically scale these projects up and to find out what works and what doesn't.
"What you're really building is an entire carbon removal industry," Larsen said. "The chances of getting to gigaton scale go down dramatically if we don't start this decade. It's way, way harder."
The momentum is growing quickly for direct air removal. Before 2018, the amount of money going to these projects in the US was miniscule -- about $11 million per year. The $3.5 billion Congress recently passed for carbon removal, as part of the bipartisan infrastructure law, is a significant increase in funding.
"There's a huge emphasis around carbon removal as a critical tool that needs to be scaled up today," Wilcox said. "We're definitely going to see the needle move in this space over the next 5-10 years."
DOE said it wants to see applications from different regions in the US that can demonstrate a high potential for carbon sequestration, can be scaled up even further and can create long-lasting jobs. It's also looking for applications from fossil fuel communities or communities with industrial capacity.
DOE officials are also aiming to create hubs that are themselves carbon neutral. For instance, the Iceland project runs on clean geothermal energy.
"Thinking about places where you're going to integrate these with other decarbonization efforts are really important," said Erin Burns, executive director of Carbon180, an organization focused on carbon removal. "We want to see these powered by zero-carbon energy, by renewables. It's essential for climate that this does not slow down or delay mitigation in any way."
Separately, DOE announced nearly $25 million for six new clean hydrogen projects in several states, including a new hydrogen production plant that captures 90 to 99% of its CO2 emissions, and new research on hydrogen fuels.