You can’t deploy marine carbon removal just anywhere. You need seawater access, affordable clean energy, existing infrastructure, and communities that won’t bear disproportionate environmental burdens. A new study just mapped where all those factors align along the US coastline.
38 Sites, 5 Hubs, 7 Criteria
Researchers identified 38 US coastal facilities with seawater intakes — power plants, desalination units, LNG terminals — and clustered them into five regional hubs: Northeast, Southeast, South, West, and Northwest.
Each hub was scored on seven criteria using a multi-criteria decision analysis:
- CO₂ removal capacity (weighted highest at 24%) — how much carbon each hub could theoretically remove
- Removal affordability (23%) — cost per unit of CO₂ removed
- Clean energy share (23%) — how green the local grid is
- Local carbon footprint (12%) — existing emissions in the area
- Hydrogen infrastructure — storage, pipelines, and demand
- Facility diversity — balance of different facility types
- Social vulnerability — exposure to environmental and socioeconomic risks
Winners and Why
The South hub (Texas and Louisiana) ranked highest on affordability, benefiting from cheap electricity generated by natural gas, wind, and nuclear. It also scores high on social vulnerability — making it a priority for equitable climate investments that bring jobs and infrastructure to communities that need them.
The West hub stood out for its clean energy share, while the Northeast hub offered the highest raw removal capacity.
The researchers used sensitivity analyses to check how rankings shifted when different criteria were weighted differently or when specific facility types (like power plants or LNG terminals) were excluded. The top three hubs remained consistently strong across scenarios.
Why Siting Studies Matter Now
Electrochemical marine CDR (e-mCDR) is one of the more promising ocean-based carbon removal approaches. It uses electricity to alter seawater chemistry in ways that increase the ocean’s capacity to absorb atmospheric CO₂. But it’s still at an early stage of development, and the gap between lab demonstrations and real-world deployment is enormous.
Studies like this one bridge that gap by answering practical questions: Where do you actually build these things? Where is the energy cheap and clean? Where does existing infrastructure reduce capital costs? Where can deployment create co-benefits rather than compounding environmental injustice?
These aren’t glamorous questions, but they’re the ones that determine whether a promising technology actually gets built.