Carbon capture at sea boosted by successful trial

Seabound trial captures 80% of shipboard emissions

A UK climate technology company has completed the first commercial sea trial of onboard carbon capture. Seabound reported that its prototype system captured around 80% of CO₂ emissions and roughly 90% of sulphur emissions during a two-month voyage on a container ship operating between Turkey and the Persian Gulf. The trial represents the first operational test of shipboard carbon capture technology on a working commercial vessel.

The significance extends beyond the technical results. Regulators accepted the captured CO₂ as verified emissions reduction, which creates a pathway for shipping operators to count onboard capture toward compliance requirements. For UK businesses with maritime supply chains or freight commitments, this regulatory recognition matters as much as the capture rate itself.

However, important questions remain about lifecycle climate impact. Recent independent analysis suggests onboard carbon capture may deliver limited net benefit when energy use, handling, transport, and storage are included in the calculation. Consequently, businesses should view this trial as evidence of technical feasibility rather than a settled decarbonization solution.

What Seabound achieved during the pilot voyage

Seabound installed its prototype carbon capture system on a commercial container ship for a two-month operational trial. The vessel ran a regular trading route between Turkish ports and destinations in the Persian Gulf. This meant the system had to perform under real working conditions, not controlled laboratory settings.

The prototype ultimately captured about one ton of CO₂ per day. Performance improved steadily throughout the voyage as the team refined operating parameters. By the end of the trial, the system was capturing approximately 78% of carbon emissions and 90% of sulphur emissions from the ship’s exhaust stream.

Independent industry reporting confirmed these figures. Trade publications noted that the capture rate increased progressively over the voyage period. Moreover, the results suggest that a full-scale installation could exceed the prototype’s performance levels once engineering refinements are applied.

The company emphasized that this was the first time shipboard carbon capture had been tested on a working commercial vessel. Previous trials had taken place on land or in controlled environments. Therefore, the sea trial provided operational evidence that the technology can function in maritime conditions with moving vessels, vibration, salt air, and variable engine loads.

Why regulatory recognition creates commercial opportunities

The trial gained attention partly because regulators accepted the captured CO₂ as verified emissions reduction. This recognition creates a potential compliance pathway for shipping operators facing tightening emissions rules. Specifically, it means captured carbon could count toward mandatory reduction targets rather than being treated as an unverified claim.

For businesses that ship goods internationally, this matters in several ways. First, freight costs may rise as shipping lines invest in emissions reduction technology to meet regulatory requirements. Companies with high shipping volumes need to understand which decarbonization approaches are likely to be accepted by regulators and priced into future contracts.

Second, some public sector tenders and large corporate supply chain standards now require evidence of freight emissions reduction. If onboard carbon capture becomes a recognized compliance method, it could appear as an option in tender specifications alongside alternative fuels or efficiency measures. Consequently, businesses tendering for contracts with sustainability criteria should monitor which technologies gain regulatory approval.

Third, the International Maritime Organization has introduced a carbon intensity indicator for ships. Vessels with lower emissions per ton-mile can gain commercial advantages. Onboard capture could improve a ship’s carbon intensity rating, which in turn affects charter rates and route allocation. Therefore, businesses negotiating long-term freight agreements may see shipping lines reference onboard capture as part of their emissions reduction strategy.

The regulatory recognition also addresses a measurement challenge. Shipping decarbonization has faced disputes over how to verify emissions reductions, particularly for novel technologies. Regulators need credible methods to distinguish genuine reductions from unverified claims. As a result, the fact that authorities accepted Seabound’s captured CO₂ as verified reduction suggests the verification methodology met regulatory standards.

Lifecycle emissions remain a contested question

A separate analysis from January 2026 argued that onboard carbon capture might deliver little or no net climate benefit when full lifecycle emissions are considered. The assessment, which examined a different pilot project run by the Global Centre for Maritime Decarbonisation, pointed to energy consumption, CO₂ handling, transport, and storage as sources of emissions that can offset the initial capture.

This lifecycle accounting matters for businesses making decarbonization decisions. Capturing CO₂ from a ship’s exhaust is only the first step. The captured carbon must then be compressed, stored onboard, offloaded at port, transported to a storage or utilization facility, and either permanently stored or converted into another product. Each of these steps requires energy and infrastructure, which generate their own emissions.

Furthermore, the energy needed to run the capture system comes from the ship’s fuel. If the vessel burns additional fuel to power the capture equipment, those extra emissions must be subtracted from the amount captured. In some scenarios, the net climate benefit can be modest or even negative, depending on the energy source and the efficiency of downstream handling.

The Seabound trial focused on technical performance at sea rather than full lifecycle analysis. Therefore, the reported 78% capture rate describes how much CO₂ the system removed from the exhaust stream, not the net climate impact after accounting for all associated emissions. These are different metrics answering different questions.

For businesses evaluating maritime emissions reduction, this distinction is important. A technology can be technically effective at capturing emissions while still producing limited net climate benefit. Consequently, procurement decisions should ask suppliers for lifecycle emissions data, not just point-source capture rates.

Additionally, the lifecycle question affects carbon accounting for businesses reporting Scope 3 emissions. If a company reports reduced shipping emissions based on onboard capture, the calculation should ideally reflect the net benefit after energy use and downstream handling. Otherwise, reported reductions may overstate actual climate impact.

Commercial shipping faces multiple decarbonization pathways

Onboard carbon capture is one of several approaches the shipping industry is exploring. Alternative fuels such as ammonia, methanol, and hydrogen are gaining attention, particularly for new vessel builds. Meanwhile, operational efficiency measures like slow steaming, hull optimization, and route planning can reduce fuel consumption without new technology.

Each approach has different cost structures, infrastructure requirements, and regulatory implications. Alternative fuels require new bunkering facilities and engine designs. Efficiency measures deliver immediate savings but have physical limits. Onboard capture works with existing fuel infrastructure but adds equipment weight and operational complexity.

For UK businesses with significant shipping activity, the choice between these pathways will likely be made by shipping lines and vessel operators rather than cargo owners. However, freight contracts increasingly include emissions clauses, carbon surcharges, or sustainability requirements. Therefore, understanding which decarbonization technologies are commercially viable helps businesses negotiate contracts and forecast costs.

Some analysts expect shipping emissions regulations to tighten significantly over the next decade. The EU Emissions Trading System now includes maritime transport. The International Maritime Organization has set targets for reducing shipping emissions by 2030 and 2050. As a result, shipping lines will need to invest in emissions reduction, and those costs will be passed through to customers.

Onboard carbon capture could become part of a mixed strategy. A shipping line might use capture technology on existing vessels while ordering new builds designed for alternative fuels. This approach spreads risk and allows companies to adapt as technologies mature and regulatory frameworks evolve.

However, businesses should be cautious about assuming any single technology will dominate. The shipping industry is diverse, with different vessel types, trade routes, and operational constraints. What works for a container ship on a fixed route may not suit a bulk carrier or a short-sea ferry. Consequently, the decarbonization pathway for maritime freight will likely involve multiple technologies tailored to specific use cases.

What UK businesses should monitor going forward

• Seabound completed a two-month sea trial on a commercial container ship, capturing approximately 78% of CO₂ emissions and 90% of sulphur emissions from the vessel’s exhaust.
• Regulators accepted the captured CO₂ as verified emissions reduction, creating a potential compliance pathway for shipping operators facing mandatory emissions targets.
• The prototype system captured about one ton of CO₂ per day, with performance improving steadily throughout the voyage.
• Lifecycle emissions analysis suggests onboard capture may deliver limited net climate benefit once energy use, transport, and storage are included in the calculation.
• The trial demonstrates technical feasibility but does not resolve whether onboard capture is the most effective decarbonization approach compared with alternative fuels or operational efficiency measures.
• Businesses with significant shipping activity should expect tightening emissions regulations and potential freight cost increases as shipping lines invest in compliance technologies.

Understanding the commercial implications for supply chains

For businesses that rely on maritime freight, the Seabound trial offers evidence that onboard carbon capture can function as an operational technology. This is relevant for companies facing pressure to reduce Scope 3 emissions, which include transportation and logistics. If shipping lines adopt onboard capture, it could appear in emissions reduction claims that suppliers make to their customers.

However, businesses should ask detailed questions about net emissions impact. A shipping line reporting reduced emissions through onboard capture should be able to explain the full lifecycle calculation, including energy use, handling, and storage. Without this detail, reported reductions may not reflect actual climate benefit.

Additionally, companies tendering for public sector contracts should be aware that carbon reporting requirements for suppliers are becoming more detailed. Some frameworks now require Scope 3 emissions data, which includes freight. If onboard carbon capture becomes a recognized compliance method, it may be referenced in tender responses. Procurement teams should understand how different technologies are verified and what the lifecycle implications are.

Freight decarbonization is also relevant for businesses with sustainability commitments or net-zero targets. Shipping emissions can be a significant part of a company’s carbon footprint, particularly for importers, exporters, or businesses with global supply chains. Therefore, understanding which maritime decarbonization technologies are credible and cost-effective helps companies plan their own emissions reduction strategies.

The regulatory landscape is changing rapidly. The EU Emissions Trading System now covers shipping, which means vessels calling at EU ports face carbon costs. The UK is developing its own emissions trading approach for maritime transport. Consequently, businesses should expect shipping costs to reflect carbon pricing in the near future.

Some businesses are already negotiating sustainability clauses in freight contracts. These clauses might specify emissions intensity targets, require the use of lower-carbon fuels, or include carbon offset arrangements. Onboard capture could become part of these contractual mechanisms if it gains wider regulatory acceptance and commercial adoption.

For companies with logistics teams or freight procurement functions, it is worth monitoring which shipping lines are investing in emissions reduction technology. Lines that move early on decarbonization may gain competitive advantages in tenders with sustainability criteria. Conversely, lines that delay investment may face higher regulatory costs and potential contract exclusions.

Industry and regulatory resources for further information

Businesses looking for detailed information on maritime emissions regulations should consult the Department for Transport’s guidance on shipping and the environment. The department publishes updates on UK implementation of international maritime emissions rules and domestic policy development.

The International Maritime Organization sets global standards for shipping emissions. The IMO’s environment page provides information on current regulations, including the carbon intensity indicator and upcoming emissions reduction targets.

For businesses reporting Scope 3 emissions from freight, guidance on carbon accounting and compliance frameworks can help ensure that reported reductions reflect actual climate impact rather than unverified claims.

Trade publications such as TradeWinds and Lloyd’s List provide ongoing coverage of shipping decarbonization technologies and regulatory developments. These sources are useful for tracking which technologies are moving from pilot trials to commercial deployment and how regulatory frameworks are evolving.