# Electrification in Maritime Vessels: Reviewing Storage Solutions and Long-Term Energy Management
## 2 Electrification of Marine Vessels  
### Environmental Aspects  
Climate change is recognized as a global emergency that demands international cooperation and solutions at all levels. At the UN Climate Change Conference (COP21) in Paris on 12 December 2015, world leaders agreed to combat climate change and its negative effects through the Paris Agreement [30]. The agreement aims to limit the global temperature increase to 2 \({}^{\circ}\)C this century by reducing greenhouse gas emissions. Furthermore, the agreement sets a more ambitious target of limiting the temperature increase to 1.5 \({}^{\circ}\)C. To achieve this, it is necessary to reduce emissions by 45% by 2030 and achieve net zero by 2050 [31]. The agreement includes commitments from all major emitting countries to reduce pollution and strengthen these commitments. It also provides avenues for developed countries to assist developing countries in climate mitigation and adaption efforts. It  
\begin{table}
\begin{tabular}{p{142.3 pt} p{284.5 pt}} \hline \hline \multicolumn{2}{p{142.3 pt}}{**Hybrid Marine Vessels:** Hybrid marine vessels combine multiple power sources, typically an internal combustion engine (often diesel) and an electric propulsion system. This setup offers operational flexibility and efficiency improvements \\ \hline Propulsion Modes & Hybrid vessels can operate in different modes, such as pure electric mode, hybrid mode (using both engines and electric motors), or internal combustion engine mode. This adaptability allows vessels to optimize fuel efficiency and emissions \\ \hline Energy Storage & Hybrid vessels have batteries that store energy for electric propulsion. This energy can come from regenerative braking, surplus engine power, or shore charging \\ \hline Advantages & Hybridization improves fuel efficiency, reduces emissions, enables silent operation in electric mode, and provides backup power in case of engine failure. It also reduces wear and tear on the main engines \\ \hline Challenges & Hybrid systems are more complex to design and maintain compared to traditional power systems. The initial investment cost can be higher due to the integration of multiple technologies \\ \hline \hline \end{tabular}
\end{table}
Table 1: _Cont._establishes a framework for transparent monitoring, reporting, and accelerating the goals of individual countries and their collective climate goals [30; 31].  
According to the requirements of the Paris Agreement, the IMO has also set a goal to decrease greenhouse gas emissions from global shipping by at least 50% by 2050 compared to 2008 [32]. Given their lengthy lifespan, this will require significant modifications to marine vessels that will be constructed in the coming years. Achieving this goal will necessitate integrating existing technologies in novel ways, developing new inventions, and introducing alternative fuels to the global market. The potential of electric energy storage systems in maritime has been overlooked despite the popularity of vehicle electrification for over a decade [33]. However, research on optimizing storage systems and charging protocols for different applications has accelerated recently.