UK-based startup Seabound recently caught the eye with the news that its ship carbon capture technology has been installed onboard the cement carrier UBC Cork. The patented system traps the ship's exhaust emissions and funnels them into a high-pressure chamber filled with calcium hydroxide pebbles, absorbing the CO2 to create calcium carbonate which, under an agreement with Heidelberg Materials, is eventually discharged at the newly-opened Brevik facility for conversion into green cement.
Seabound’s system is suitable for all ship types but, notwithstanding the novelty that it will offload limestone at the cement industry’s first major carbon capture project, it highlights a predicament facing cement carriers more generally. The UBC Cork, which was built in 2009, is a relatively young ship by the standards of the global cement carrier fleet, where the average age is 26 years, according to shipping analysis firm Clarksons Research. Many vessels are over 30 years old (around 30 ships are over 50 years) and, like the bulk sector, generally their hullforms, propulsion systems, cargo holds and layouts lag behind the kinds of innovations found on tankers, container ships and offshore vessels.
With ageing tonnage and an array of challenges related to the decarbonisation of shipping, it is not difficult to see how the Seabound system, a relatively cheap solution – estimates put the cost at tens of thousands of dollars, although optimal efficiency will inevitably cost more – with proven chemistry would be appealing.
Maritime decarbonisation
Like cement, commercial shipping is also a hard-to-abate sector when it comes to carbon emissions and the appeal of carbon capture is self-evident. Due to its unique nature the maritime industry, under the governance of the UN-affiliated International Maritime Organisation (IMO), was charged with developing its own regulatory instruments and roadmap to meet the objectives of the Paris Agreement. This eventually coalesced into two main instruments: an energy efficiency rating for each individual ship and the Carbon Intensity Index (CII), a rating system that measures how efficiently a ship transports goods or passengers, expressed in grams of CO2 emitted per capacity and distance travelled. Ships receive an annual rating from A to E, with A being the best, but the emissions standards to receive a given rating become stricter each year.
This is where things become tricky for cement carriers. As older, less efficient vessels, many are likely to receive lower CII scores. Under IMO’s plans, any vessel that receives a D rating for three consecutive years, or E in a single year, must take corrective steps to achieve a C rating or better. Failure to do so and the ship could be detained in port and banned from operating. It should be stressed that beyond making improvements to the vessel itself there are steps that can be taken to reduce emissions, reducing the ship’s speed being the principal one. However, this will inevitably lead to an increase in operating costs, make the ship less attractive to charterers and other stakeholders, and eventually become unsustainable as the CII requirements tighten.
New fuels and technologies
Like land-based industry, the maritime sector is heavily engaged in the challenge of lowering its carbon emissions. For larger ships such as cement carriers full electrification is not really an option and much of the focus is on carbon-neutral and zero-carbon fuels such as methanol and ammonia. Notwithstanding that these fuels are still not fully tested, there are serious concerns about fuel (bunkering) infrastructure and scalability. Moreover, comparatively few bulk carriers, let alone specialised cement carriers, are currently being built that would be ready to switch to these fuels.
A notable exception are two cement carriers currently being built for Nova Algoma Cement Carriers (the specialist operator in which P&O Maritime has recently taken a controlling interest). The first, ordered last year, is a 38,000dwt ship that will have methanol dual-fuel capability and is scheduled for delivery at the end of 2026. The second, announced in April, will be under the commercial operation of Holcim and methanol-only, cutting CO2 emissions by 60 per cent compared to a conventional vessel. The pair will share the distinction of being the world’s largest pneumatic cement carriers. Although Nova Algoma does also run some vessels on liquefied natural gas (LNG) it remains something of an outlier.
For other operators, a more economically viable option for emissions reduction may be wind assisted ship propulsion (WASP), which is expected to become commonplace on many merchant ships over the next few years. Two cement carriers are currently employing different WASP technologies: Eureka Shipping’s Sunnanvik is using the VentoFoil system on North America’s Great Lakes, while the 2024-built Cemcommander has a Norsepower rotor sail funded by the German government.
Like other merchant ships, it is likely cement carriers will mix and match technologies, combining energy-saving devices with nascent carbon capture technology to achieve the requisite emissions profile.
