## 2 Integration of Carbon Capture Technologies in Ships: Status and Requirements
\begin{table}
\begin{tabular}{p{142.3 pt} p{284.5 pt}} \hline \hline
**KPI** & **Description** \\ \hline
**Maturity** & Whilst land-based CCS is relatively mature, only limited demo cases are available for maritime CCS and at low capture rates. \\
**Compactness** & On-board space capacity is limited. The minimization of system dimensions and weight is important for on-board integration. \\  & The solvent needs to be effective within a range of variant operating conditions, including temperature, pressure, exhaust gas flow and CO\({}_{2}\) content in the exhaust. When powered by LNG, the CO\({}_{2}\) content in ship engine exhaust is about 4–6%, which is lower than that of land-based applications. Solvents need to be effective at such low CO\({}_{2}\) content increasing the energy penalty for CO\({}_{2}\) capture. \\
**Energy penalty** & Unlike land-based applications, the on-board ship environment has low availability of power, heat, and consumable resources. Therefore, the energy demand for regenerating the solvent must be kept as low as possible. \\
**Impurity tolerance** & Some solvents may be sensitive to impurities, e.g., sulfur, particulate matter, or methane traces, or their capture efficiency may be degraded in the presence of such compounds in the flue gas. Any requirement for pre-treatment equipment would add complexity, risk, volume, and weight. \\
**CO\({}_{2}\) product characteristics** & The CO\({}_{2}\) product form is important in accounting for on-board storage capacity and conditions (liquefied, compressed, etc.), thus affecting the on-board resource requirements. \\
**CO\({}_{2}\) loading** & The molar ratio of CO\({}_{2}\) over the pure solvent. It is often regarded as a measure of the solvent’s capacity for CO\({}_{2}\) capture (i.e., higher loading leads to more CO\({}_{2}\) captured per unit of solvent) and can be correlated with solvent needs, regeneration demands, and the capture efficiency within the process. \\
**OPEX** & Cots are associated with large uncertainties and impact the uptake of technologies in the industry. Costs include maintenance and consumables, as well as any additional fuel costs as a result of the energy penalty. Degradation of solvent performance through use also plays important role in OPEX costs. \\
**Other consumables** & Depending on the solvent, other consumables may be needed, for example, water. Such demands increase the on-board requirements for energy and storage capacity. \\  & The solvent physicochemical properties, e.g., Hammability and toxicity, may impose health and safety hazards that require assessment, monitoring, and prevention measures. In addition, operational features such as high pressure or temperature impose additional design considerations related to safety as the key properties that determine the flammability of a material (such as lower-upper flammability limits, flash point, autoignition temperature, minimum ignition energy, and laminar flame speed, e.g., [23]) are strongly dependent on the temperature, pressure, and geometry of the container or reactor. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Key performance indicators for on-board solvent-based CO\({}_{2}\) capture.