Carbon capture and storage (CCS) can contribute to decarbonisation of the maritime industry, especially when combined with other approaches. CCS allows ships to continue using fossil fuels while capturing and storing the emitted CO2.
It’s a helpful interim approach if a vessel’s immediate transition to alternative fuels is not feasible due to infrastructure limits or technology constraints. CCS can extend a vessel’s operational lifespan, both reducing emissions from existing vessels while avoiding premature scrapping and associated environmental impacts.
Technology challenges
There are technology challenges, such as higher fuel consumption and process costs for ships
As the industry works toward the use of zero-emission fuels such as green hydrogen, ammonia and methanol, CCS offers a more gradual and realistic pathway to decarbonisation. CCS is also an attractive option for long-haul shipping routes where alternative fuel infrastructure may be limited.
However, there are technology challenges, such as higher fuel consumption and operation costs for ships. Space constraints are another obstacle considering the needs to operate and install CCS equipment on board ships.
Clear and supportive regulation
More work is needed to provide secure and reliable long-term storage of captured CO2, which is still under development.
Technology advancement and government incentives are also needed to increase the economic viability of Carbon Capture and Storage for ships operators. Clear and supportive regulation paves the way for widespread adoption of CCS in the maritime sector, including standards for capture, transport, and storage.
Carbon capture and storage
The amine solution, now loaded with CO2, is then sent to a regenerator (stripper)
In a CCS system, carbon dioxide (CO2) is captured from a ship’s exhaust gases after the fuel has been burned. This often involves chemical absorption, in which the exhaust gases pass through a solvent that absorbs the CO2. A contactor (absorber) uses an amine solution to react chemically with the CO2, forming a carbamate compound. This effectively removes the CO2 from the flue gas.
The amine solution, now loaded with CO2, is then sent to a regenerator (stripper). Heat is applied to the solution, causing the carbamate to decompose, releasing the captured CO2.
Onshore storage sites
The CO2 is then separated and stored onboard in high-pressure tanks as a liquid, and later offloaded at designated ports for transport to onshore storage sites.
There is an energy penalty in the process, since CCS itself requires energy, which can increase fuel consumption and operating costs for the ship. Because onboard storage capacity for captured CO2 can be limited, frequent offloading is required.
Adoption timeline for CCS
Most CCS projects in the maritime sector are still in the research and development phase
In the near term (5 to 10 years), initial deployments of CCS on select vessels will likely focus on niche applications or specific routes. Most CCS projects in the maritime sector are still in the research and development phase. Some pilot projects and demonstrations are underway to test the feasibility and effectiveness of CCS technologies, but large-scale commercial deployments of CCS systems on board ships are still to come.
If technological advancements and economic viability improve, CCS could see more widespread adoption in the maritime sector within the next 10 to 20 years, particularly for vessels where alternative fuel options are limited or not yet feasible. The development of a robust infrastructure for the transport and storage of captured CO2 will be crucial for the large-scale deployment of CCS in the maritime.
Requirements of CCS systems for maritime use
Looking long-term (20 years or more), CCS could become a mature technology integrated into the broader maritime decarbonisation landscape, potentially playing a role alongside other technologies like alternative fuels and energy efficiency measures. Continued research and development will aim to improve the efficiency, cost-effectiveness, and space requirements of CCS systems for maritime use.
The development of more efficient and compact CCS systems is crucial for their widespread adoption in the maritime sector. Reducing the costs, including capital expenditures and operational expenses, is also essential. Clear and supportive regulations, including carbon pricing mechanisms and incentives for CCS deployment, will encourage its adoption.
Complementary technologies toward decarbonisation
Another option is using fuel cells to convert hydrogen or other fuels into electricity for propulsion
CCS can be used in conjunction with transitional fuels like Liquefied Natural Gas (LNG), capturing and storing CO2 emissions from LNG-powered vessels to reduce the carbon footprint while the industry transitions to zero-emission fuels. CCS can be particularly valuable for sectors where zero-emission alternatives may not be readily available or feasible, such as long-haul shipping. CCS can also serve as a backstop technology, providing a potential solution for residual emissions from alternative fuel pathways, even if they are considered low-carbon.
A range of alternative fuel scenarios drive research and development into new technologies such as biofuels, green hydrogen, ammonia, and methanol. Another possibility is using fuel cells to convert hydrogen or other fuels into electricity for propulsion. Better battery technology, including better capacity and charging infrastructure, is needed. And ship designs must be optimised for alternative fuels, including storage and handling systems.
Next stages for CCS
The next stage in the development of carbon capture and storage (CCS) for maritime vessels will likely involve full-scale demonstration projects, moving beyond small-scale prototypes and lab tests to real-world applications on commercial vessels. More compact and lightweight systems will be developed to reduce the weight and space requirements on board ships.
Viable business models and financial mechanisms are needed to make CCS economically attractive for ship owners. A clear and consistent regulatory framework can incentivise CCS adoption and ensure compliance with environmental standards. There also needs to be more public awareness and understanding of the role of CCS in decarbonising the maritime sector.