PITTSBURGH – We’re familiar with the idea of reducing carbon dioxide emissions form power plants and factories. But reaching the federal government’s goal of net-zero CO2 emissions by 2050 requires something else: taking it out of the air.
The National Energy Technology Laboratory’s Direct Air Capture Center in Pittsburgh is working to help industry and academic researchers figure out best ways to do that.
We need to pull about a gigaton of CO2 per year from the atmosphere to reach the net-zero goal, said
David Luebke, technical director for NETL’s DAC Center.
And NETL has 25 years of experience working on point-source capture, he said. With the DAC, NETL wants to leverage its expertise to work with technology developers across industry and academia to help them rapidly scale up and commercialize DAC technology.
Scaling up requires a lot of capital expenditure. With NETL’s facility, “we basically encourage them to develop those technologies because they’re not having to invest the cap-ex themselves for the test systems.”
You might ask why not plant a lot of trees instead of building big machines. One reason, he said, is that reforestation is good but not sufficient. We took a lot of CO2 out of the earth – fossil fuels for instance – that wasn’t stored in trees.
Another is land use. One mature tree takes 48 pounds of CO2 per year from the air. Some small pre-commercial systems in operation remove 4,000 tons per year – about 160,000 trees.
And there’s no real worry about taking out so much that we starve the trees and plants, he said. Net-zero just means we stop increasing the amount in the atmosphere.
Luebke took us to the room where two small prototypes are set up. The smaller of the two – about 6 feet long and 3 feet high – is the functional equivalent of one tree. It’s a material-scale prototype.
DAC requires an absorbent that will capture the CO2 from the air that passes by or through it. (Sending off the CO2 for sequestration or conversion into other products is a whole separate field.)
This prototype system sets conditions of the air the material sees – the temperature, moisture and so on, essentially the weather – to help determine the longevity of the material being tested. A small reactor – a metal tube about 18 inches long and about 2 inches in diameter – is where the DAC absorption takes place.
“This system is basically designed to do that with very little operator intervention,” he said. You load the material, put it in the system, program it, and it runs for months on its own.
Its bigger roommate is a module-scale unit for testing materials in various forms. He shows some small rectangular plates about 3-by-5 inches – that can be stacked inside the module reactor about 12-by-12 inches. The idea to turn the material into a form that can be scaled into a full-size DAC unit for an industrial operation.
The little plates are just one type of DAC material. They could also look like a house air filter, for instance.
From the small, white room we move to a huge bay, two stories high, with huge garage doors. This summer, they will set up two environmental chambers about 20 feet high for DAC prototypes about the size of a shipping container that will be able to duplicate various weather conditions.
And NETL will also provide computer modeling of whatever energy source the client wants to use to power the DAC unit – whether wind or solar or waste industrial heat or something else – and control how the energy flows into the DAC unit. They can get the data on how it will work in real world without having to go out and build it.
NETL wants to have five full-size systems in operation by next year, he said. They expect construction to be complete about this time next year.
Right now they have a half dozen or so companies waiting to test their DAC technologies, he said. When up to full speed they will have 17 independent systems up and running.
Clients will pay NETL the amount necessary to offset its costs, he said.
In 2022, Congress authorized $25 million for the DAC Center. Luebke said they met with industry leaders to learn what they were looking for in a DAC testing facility and tailored their design to meet the need. It will be able to test DAC units under conditions representing the extreme ranges of climate within the contiguous United States, at scales up to a small pilot.
The developers will also have access to NETL’s suite of process modeling and analysis tools to evaluate the economic and life-cycle aspects of their technologies, Luebke said.
Email: dbeard@dominionpost.com
