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As the U.S. continues to seek ways to reduce greenhouse gas emissions in order to reach its net-zero goal by 2050, researchers are looking at a number of innovative technologies to help meet climate goals and stave off global warming.
Dr. Dave Luebke, technical director of the National Energy Technology Laboratory’s Direct Air Capture Center, said that one important technology under development is direct air capture (DAC) of carbon dioxide (CO2) from the atmosphere. Luebke was the speaker for “The Future of Carbon Capture,” an hour-long webinar presented by the W&J College Center for Energy Policy and Management. The webinar can be viewed here.
DAC uses various technologies to filter CO2 directly from the atmosphere at any location. If differs from point-source carbon capture, which removes CO2 at the point of emission at large-scale sources, such as power plants, steel plants and cement plants. The CO2 is then compressed into a liquid and injected under high pressure into deep geological formations for permanent storage.
Luebke explained that the nation’s current energy mix is close to 15% renewables and 8.4% nuclear. The remaining almost 80% is from fossil fuels, all of which generate CO2. While continued increases in renewable sources, efficiency improvements, and a move away from coal will bring down emissions, there will still be a “last chunk” of emissions that cannot be easily reduced, mostly from the industrial and transportation sectors. In order to offset those emissions to get to net-zero, carbon capture will be a part of the solution.
Direct air capture technology is still largely in the development and discovery phase, he said, and NETL has been working in the area of carbon capture for 20 years. DAC currently costs about $600 to $700 per ton of CO2 removed from the atmosphere, which is prohibitively expensive.
In order to be able to remove a gigaton – a billion tons – of CO2 from the atmosphere each year, the cost must be reduced to $100 a ton over the next decade using technology that is scaleable to megatons. The government’s Carbon Negative Shot is trying to quickly ramp up that technology.
There are two approaches to DAC, using solvents and sorbents to capture CO2. Solvents are liquids good at absorbing CO2, while sorbents are solids, such as fibers that can be built into filters, to absorb CO2.
The Bipartisan Infrastructure Law provided $3.5 billion to help fund four regional Direct Air Capture hubs to help bring the technology to scale, and NETL’s Direct Air Capture Center, which Luebke oversees, is also working to develop the needed technologies. The facility in the Pittsburgh area is testing materials and systems in the prototype stage, taking the information learned and putting together suites of technology that will eventually be used at scale. The center can also test technologies under various atmospheric conditions to mimic various climates in the U.S.
As DAC technology continues to develop, Luebke noted that it must be evaluated on both the economic and environmental benefits, with the cost coming down as the use increases.