How a London startup is transforming shipping emissions into usable limestone for greener cement—and changing the future of two polluting industries
Turning Shipping Emissions Into Cement Ingredients
Shipping is a major source of global carbon pollution, but a London-based startup, Seabound, is charting a new course.
- Its carbon capture system transforms a ship’s CO₂ emissions into limestone, a crucial ingredient for cement production.
- The UBC Cork, a Mediterranean cement carrier, is the first vessel to test this innovation.
How It Works: Carbon Capture at Sea
Seabound’s system retrofits existing engines—no need for expensive new ships.
- CO₂ from the ship’s exhaust is captured and chemically converted into limestone pellets.
- When the UBC Cork docks in Norway, the limestone byproduct is offloaded to Heidelberg Materials’ net-zero cement plant in Brevik.
- This closes a carbon loop: emissions from shipping are converted and reused in making more sustainable cement.
Why Cement and Shipping Emissions Matter
Both shipping and cement are heavy carbon emitters—shipping accounts for 3% and cement for 8% of all global CO₂ emissions.
- Shipping: Batteries aren’t energy-dense enough for long voyages, limiting the impact of electrification.
- Cement: Producing Portland cement inherently releases CO₂ during the chemical process, even before accounting for fuel use.
The Urgency: New Industry Rules
The International Maritime Organization (IMO) is pushing for deep cuts in shipping pollution.
- Fleet owners must reduce greenhouse gas emissions by 30% in the next decade, and up to 65% by 2040.
- Solutions like Seabound’s offer a practical retrofit—helping ships meet new standards without complete engine replacement.
Other Approaches: Amogy’s Ammonia Power
Seabound isn’t the only innovator tackling shipping’s climate challenge.
- Amogy is developing ammonia-cracking technology to power ships with zero emissions.
- Ammonia is energy-dense but requires significant engine overhauls or replacements, posing a higher upfront hurdle for most shipowners.
A Greener Future for Cement and Shipping
Seabound’s system not only cuts emissions but creates a valuable product for cement production—addressing two major pollution sources at once.
- Heidelberg Materials plans to use the captured limestone, further reducing the carbon footprint of its cement.
- The approach demonstrates how creative retrofits can drive change now, without waiting for entirely new infrastructure.
