Amid increasingly urgent calls for more radical climate change action, a team of South Korean scientists has found a way to kill two birds with one stone by converting carbon dioxide into electricity and hydrogen.
The team, from the Ulsan National Institute of Science and Technology, took as a starting point of their research the fact that when CO2 is absorbed into the sea—which is where most CO2 emissions end up—the acidity levels of the water rise. As per their report, “If acidity increases, the number of protons increases, which in turn increases the power to attract electrons. If a battery system is created based on this phenomenon, electricity can be produced by removing CO2.”
The system that the researchers invented very much resembles a fuel cell in which the reaction starts when CO2 is injected into the water, which contains the catalyst necessary for the reaction and the sodium metal cathode. The team reports the system has a pretty high conversion efficiency at 50 percent and has operated for more than 1,000 hours without the electrodes sustaining any damage.
Ideally, the system could be deployed to capture and convert emissions from fossil fuel-powered facilities into hydrogen, to be used in its turn as vehicle fuel. However, this is early-stage research. According to the lead co-author of the research, Professor Jeongwon Kim, “This research will lead to more derived research and will be able to produce H2 and electricity more effectively when electrolytes, separator, system design, and electrocatalysts are improved.”
It’s good to have research like that to spur further work in the field and eventually, hopefully, it’ll lead to practically applicable electricity generation systems that at the same time reduce the world’s carbon footprint. However, we will have to wait quite a while longer.
Systems such as the one designed by the UNIST scientists rely on carbon capture and storage. This approach to reducing carbon emissions has been garnering quite a lot of attention but it remains more a topic of discussion than a technology that’s being adopted widely. The reason: prohibitively high costs.
The costliest part is the capture. The Carbon Capture and Storage Association estimates the cost of capturing carbon emissions from fossil fuel burning at about US$70-102 per ton. The same association predicts these could fall to around US$40-57 over the next few years, with hopes that carbon capture technology will follow the cost-falling path of lithium ion batteries. However, it is far from certain it will work out that way.
Back in 2016, a Clean Technica author, business consultant Michael Barnard, calculated the total cost of capturing, transporting, and sequestering (long-term storage) a ton of CO2 at US$120-140. This translates into US$140-164 trillion for the capturing, transportation, and sequestration of more than 1,100 gigatons of CO2 if we are to return to CO2 levels from before the Industrial Revolution, according to Barnard.
It is in this respect that the UNIST breakthrough is very important: it eliminates the need to store the captured CO2 for any considerable length of time. Using it to produce electricity could significantly cut the costs associated with the whole carbon capture and storage affair.