This is exciting to me: https://www.gasworld.com/story/equatic-unveils-plans-for-largest-ocean-based-carbon-removal-plant/2134731.article/
From the authors:
'On a grid-wide basis (U.S. average emissions factor of 743 g/kWh of electricity) and setting solar electricity (emissions factor of 25 g/kWh of electricity) (3) as a baseline zero-carbon electricity reference, it is important to ask whether renewable energy should be used to (1) displace fossil fuel-based power generation or (2) used to power NETs. The answer is complex, but in short, it depends on the energy intensity of the CO2 removal process. For the case of NGC-based electricity generation, in general, a NET needs to feature an energy intensity of no more than 1.34 MWh per t of CO2 removed. The conclusion is that the sCS2 process as outlined herein, if deployed in a format where the energy in the cogenerated H2(g) can be recovered (0.8–1.2 MWh per t of CO2 removed), features an energy intensity that is sufficiently low to be worthy of deployment as a renewable energy powered NET, rather than displacing sources of NGC-powered electricity generation by renewable energy generation.' [1]
As for permanence of storage, most experts believe that "Furthermore, storage of CO2 as solid carbonate minerals or dissolved bicarbonate is permanent in human relevant timescales."[2; Geological Chapter] In the Equatic case, CO2 mineralization (ex-situ) is stored as Calcite (CaCO3). As such, it is expected to be very long term storage. I know there is data on the stability of calcite in nature[2], and storage is expected to be millions of years.
As for impact on ocean, all that is removed is carbonates which CO2 converts to during the pH changes. The pH is then returned to the Ocean's pH before effluent is returned to the ocean.
Is it better than BECCS? I think it is competitive. With that said, BECCS with Oxy-fuel and chemical looping technology might be hard to beat.
References:
[1] La Plante, E. C., Simonetti, D. A., Wang, J., Al-Turki, A., Chen, X., Jassby, D., & Sant, G. N. (2021). Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO2 Management. ACS Sustainable Chemistry & Engineering, 9(3), 1073–1089. https://doi.org/10.1021/acssuschemeng.0c08561
[2] Greenhouse Gas Removal Technologies. (2022). United Kingdom: Royal Society of Chemistry.
[3] Reiner, D., Bui, M., & Mac Dowell, N. (2019). Carbon Capture and Storage. The Royal Society of Chemistry. https://doi.org/10.1039/9781788012744
I am sorry to insult your sources, but it is foolish "to ask whether renewable energy should be used to (1) displace fossil fuel-based power generation" -- of course it should be used to do so, in fact to shut down "fossil fuel-based power generation" COMPLETELY. Any other point of view in today's world with Clean Energy now already cheaper than fossil power is only a ploy to keep the $$ flowing to the fossil industry and nothing more. It is a foolish thought in the entirety to say "it's okay to waste available clean energy to offset my bad action" -- WRONG! Every dumb bad fossil energy use where already economically replaceable with clean energy Must End ASAP, Period. Any other reading or perspective is dangerous for our collective future by continuing to damage our planet.
Yes, from a systems perspective, it makes sense to replace all fossil fuel before we start carbon dioxide removal technology because not doing so emits more CO2 overall. I was taught that by Dr. Joshi of Berkeley and Dr. Jacobson from Standford.
With that said, we have to do research on CDR technologies, and that involves a pilot plant. So, I believe an islanded system with renewable energy is better than an islanded system with fossil fuels. If political will was such that wind, water, solar, and storage was built out faster, we wouldn't have to worry about the above analysis that UCLA has done.
I don't think UCLA and Equatic are collaborating with Oil and Gas to keep fossil fuels on the grid.
Finally, I always learn from you, so I am never insulted. You are a very well respected MIT graduate! You have done wonderful things!