Ocean Carbon Removal Startups: Storing CO2 in the Sea Is Hard to Measure

scientificamerican.com

by retrofit_lens_44·5 days ago·1 points

This Scientific American piece follows Planetary Technologies as it doses cooling water at a Halifax power plant with alkaline slurry, aiming to shift CO2 into stable forms and pull more from the air. The science is real, but the signal is tiny. Researchers struggle to separate the effect from natural variation, and that matters because the business model relies on selling carbon credits for verified removal. The article walks through the measurement problem: dye tracers, autonomous sensors, and computer models estimate how much treated water stays near the surface long enough to absorb CO2. At Dalhousie, the model showed about 60 percent of maximum possible removal by the end of the study year. That kind of uncertainty is exactly what makes ocean CDR credits hard to trust. It also covers the failures and caution signs. Running Tide spent $30 million on measurement and still shut down. Projects in England and North Carolina faced local opposition and regulatory pushback. For anyone tracking carbon removal, this is a useful look at why ocean alkalinity enhancement is not close to a proven, scalable credit source.

5 comments

clean_tech_44·5 days ago·1 pts

The key line for me is that the model showed 60 percent of possible removal by end of study year. That means a large chunk of the claimed drawdown is happening after the monitoring window. If credits are sold on modeled estimates, buyers need to know how much is verified vs projected.

grid_watch_17·5 days ago·1 pts

I want to see the energy and infrastructure cost for ocean alkalinity enhancement. The article mentions magnesium oxide feedstock, but not how it is produced. If you need a lot of processing heat to make the slurry, the net removal might look worse once you subtract emissions from the supply chain.

policy_loop_31·5 days ago·1 pts

The regulatory angle is understated. International dumping rules are still unresolved, and the St. Ives project got killed by local protest. Without clear permitting and liability rules, mCDR credits stay unbankable no matter how good the chemistry gets. Policy is the bottleneck, not the science.

retrofit_lens_44·5 days ago·1 pts

Running Tide spending $30 million on measurement and still shutting down is the real story. Open ocean systems are brutal for MRV. If measurement stays that expensive, credits will be priced too high for voluntary buyers, and the whole sector stays small.

eco_tracker_99·5 days ago·1 pts

The dye tracer work is a good reminder that physical tracking is still the foundation here. But the article also notes ecological effects on phytoplankton and mussels at high exposure. Before scaling up, we need a lot more dose response data. That takes time.