## 1 Introduction
The above regulations present a new operating environment for the shipping industry where novel materials, processes, designs, and operational practices need to be defined, evaluated, and introduced in new and existing vessels at a fast pace. Proposed strategies can generally be classified in five broad categories:  
1. Alternative fuels (the vast majority (>95%) of sea-going vessels is operated with either heavy fuel oil (HFO) or marine diesel oil (MDO). Liquefied natural gas (LNG) is mainly used as a fuel in LNG carriers. Potential alternative fuels being considered bythe maritime industry include ammonia, methanol, liquefied petroleum gas (LPG), and biofuels (including bio-oils and hydrotreated vegetable oils (HVOs));
2. Propulsion and power system (engine efficiency improvement, propulsion efficiency devices, propeller optimization, waste heat recovery, and wind and solar assistance technologies);
3. Electrification (on-board electricity production, fuel cells, battery storage, hybrid systems, and cold ironing);
4. Ship design (hull hydrodynamics, hull coatings, and air lubrication);
5. Operational measures (slow steaming, weather routing, route optimization, and ship energy management system integration). Several recent studies in the open literature have attempted to assess the effect of the above measures and strategies on the overall ship energy efficiency and GHG emission reduction potential and have identified limitations to their wide deployment. For example, [PERSON] et al. [7] and [PERSON] et al. [8] have concluded that the introduction of biofuels can, in principle, result in a 100% reduction in GHG emissions. However, there are several technical and operational issues--such as engine compatibility, long-term storage, and bunkering infrastructure--that severely limit its applicability potential. Most stand-alone technical and operational measures, with the notable exemption of slow-steaming, can only achieve modest reductions in GHG emissions; see for example the comprehensive work of [PERSON] et al. [9]. It is only through the optimized combination efficiency improvements, alternative fuels, and targeted operational measures that the IMO goals can be potentially met. This, however, will inevitably lead to increased system complexity and increased capital and operating costs. An emerging alternative solution that can be both technically and financially feasible and offer a very high decarbonization potential is carbon capture utilization and storage (CCUS). CCUS offers the alternative of directly removing carbon emissions from an industrial process (or even directly from the atmosphere) and possibly reusing part of the captured carbon as valuable raw material for the synthesis of new fuels and/or chemicals [10]. Multiple scenarios have been developed that attempt to predict the beneficial influence of CCUS technologies in the global emissions map, including the Blue Scenario Map from the International Energy Agency (IEA). According to the IEA [11], CCUS is crucial in the so-called beyond 2 \({}^{\circ}\)C scenario (B2 DS) for limiting temperature rise below 2 \({}^{\circ}\)C by 2060. The B2 DS sets out a rapid decarbonization pathway with CCS being the key driver and responsible for a massive 32% CO\({}_{2}\) emission reduction beyond the 2 DS scenario. Currently, only a small fraction (almost 230 Mt) of the carbon emitted is re-used in agriculture, oil, and gas as well as food industries, with new routes of exploitation being developed for the building, fuels, and chemicals sectors [12]. However, the demand of these sectors for CO\({}_{2}\) is not expected to meet the actual capacity of captured carbon, leading to the development of disposal and sequestration options to balance the carbon market. Carbon capture relies predominantly on the successful separation and removal of CO\({}_{2}\) from a flue gas stream and is classified mainly as pre-combustion, post-combustion, and oxy-fuel combustion CO\({}_{2}\) capture [13].