Climate Wire | There is a growing consensus among climate scientists that humanity must find ways to sequester carbon dioxide to avoid the worst effects of global warming. Most of the efforts to date have focused on removing CO2 from the atmosphere.
But two ongoing efforts, including one from the Massachusetts Institute of Technology, are aimed at the ocean, not the atmosphere. And if successful, scientists say, it could significantly reduce the cost of using carbon capture to combat global warming.
One big reason? “In the ocean, the capture step has already taken place,” said T. Alan Hutton, a chemical engineering professor and leader of his MIT team. Energy and Environmental Science.
That’s because the oceans are the planet’s major ‘carbon sink’, absorbing 30-40% of greenhouse gases from the atmosphere.
“Additionally, the density of greenhouse gases in the ocean is more than 100 times higher than in air,” Hutton added. “This means that the amount of material that needs to be handled in ocean capture is much less than air capture operations, further simplifying the overall process.”
The MIT report describes a two-step “electrochemical” process that extracts CO2 from seawater. The first step uses electricity to temporarily acidify the water to help remove CO2. The second step removes acidity and captures CO2.
Kripa Varanasi, a professor of mechanical engineering and co-author of the MIT report, said in an interview that MIT’s approach is both energy cost and costly to remove the expensive membranes used to capture CO2, as diesel-powered merchant ships can’t handle enough CO2. was reduced to a collectible level. to offset their emissions.
Other ships “could be sea scrubbers,” he said. This is an attractive step even for small countries whose income depends on tourism, aquaculture and fishing, which could otherwise be severely harmed by the warming waters brought on by climate change.
MIT is one of two major US efforts to investigate ocean CO2 removal processes. Earlier this month, Captura Corp. — a company spun out of Caltech — issued a press release announcing the start of its first pilot plant near Newport Beach, California. pacific ocean.
The company uses a process that relies on electrolysis and membranes to remove CO2 from seawater. It has received financial support from the Saudi Arabian Oil Company, which believes its large-scale water desalination plant could be used for CO2 removal. Also, his $1 million grant from his XPRIZE competition on carbon removal was awarded through his $100 million donation from billionaire Elon Musk.
Hutton said the MIT effort, which started later than Caltech, hopes to enter the competition when technology research is finished within the next year. Noting that the MIT research he began two years ago with a grant from the Department of Energy’s Advanced Research Projects Agency-Energy, he said, “Hopefully it’s not a better one. I hope it will be as good, if not better.”
Billed as the largest incentive award in history, the XPRIZE seeks to spur global competition among companies, governments and investors who can find effective ways to remove 10 billion tons of CO2 annually by 2050. Designed to
The final XPRIZE winner will be announced on Earth Day 2025. The most promising removal technology will get him $50 million, with his next three participants splitting his $30 million.
What this means for the MIT effort is that the ultimate CO2 harvesting operation would have to be very large. Planners there are looking to turn CO2 into fuels such as ethanol and products such as concrete.
But underground geological storage areas, such as depleted oil reservoirs, are likely to get most of the ocean-derived CO2, Hutton said.
“You can’t use everything as feedstock.
Reprinted from E&E News with permission of POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environmental professionals.
