Dr. Gary O’Bireck

Today we are hearing more about the notion of capturing carbon dioxide from the atmosphere to help fight global warming. Now, a new study indicates negative emissions technologies could be part of the effort to do just that.

Negative emissions technology refers to the use of electricity from renewable sources to create hydrogen fuel and capture carbon dioxide. More specifically, carbon dioxide is captured from the atmosphere via an “electrogeochemical” process that also produces hydrogen gas that can be used as fuel, while creating by-products that may help offset ocean acidification. As recently noted by UC Santa Cruz, Greg Rau, who is a researcher in their Institute of Marine Sciences and a visiting scientist at Lawrence Livermore National Laboratory, this technology significantly increases available options for negative emissions energy production.

As concluded by the Intergovernmental Panel on Climate Change, limiting global warming to 2 degrees Celsius requires both the reduction of emissions of carbon dioxide and the energetic removal of carbon dioxide from the atmosphere. In a new study published on June 25, 2018 in Nature Climate Change, Rau and his research group strongly suggest that negative emissions technologies are integral in accomplishing this aim. The various methods mentioned generally use electricity from a renewable energy source to cause the electrolysis of saline water. This action generates hydrogen and oxygen, while also causing reactions involving globally plentiful minerals, to produce a solution that effectively absorbs and retains carbon dioxide from the atmosphere. All related methods involve electrochemistry, saline water, and carbonate or silicate minerals.

In Rau’s view, “It not only reduces atmospheric carbon dioxide, it also adds alkalinity to the ocean, so it’s a two-pronged benefit. The process simply converts carbon dioxide into a dissolved mineral bicarbonate, which is already abundant in the ocean, and helps counter acidification.” While electrogeochemical methods have only been demonstrated in laboratory settings, additional research is required to scale them up. Actual approaches would be optimally located in coastal areas or offshore with easy access to saltwater, abundant renewable energy, and minerals. Since electrogeochemistry appears adept at capturing carbon, producing fuel, and offsetting ocean acidification, perhaps this process will contribute to reaching the aim of limiting global warming.