# Comparative Analysis of Marine Alternative Fuels for Offshore Supply Vessels
## 2 Methodology
### Economic Impact
\begin{table}
\begin{tabular}{l l l l l l l} \hline \hline \multirow{2}{*}{**Fuel**} & \multirow{2}{*}{**Case**} & \multirow{2}{*}{**Fuel Type**} & \multicolumn{2}{c}{**Cost Rating**} & \\ \cline{3-6}  & & & **CapEx** & **OpEx** & **Fuel Cost** & **Sum** \\ \hline \multirow{8}{*}{Ammonia} & \multirow{2}{*}{Mechanical propulsion} & Grey & 5 & 5 & 5 & 15 \\ \cline{3-6}  & & Blue & 5 & 5 & 3 & 13 \\ \cline{3-6}  & & Green & 5 & 5 & 2 & 12 \\ \cline{3-6}  & & Grey & 5 & 4 & 3 & 14 \\ \cline{3-6}  & & Blue & 5 & 4 & 3 & 12 \\ \cline{3-6}  & & Green & 5 & 4 & 2 & 11 \\ \cline{3-6}  & & Grey & 3 & 2 & 5 & 10 \\ \cline{3-6}  & & Blue & 3 & 2 & 3 & 8 \\ \cline{3-6}  & & Green & 3 & 2 & 3 & 8 \\ \cline{3-6}  & & Grey & 2 & 1 & 5 & 8 \\ \cline{3-6}  & & [PERSON] & 2 & 1 & 3 & 6 \\ \cline{3-6}  & & [PERSON] & 2 & 1 & 4 & 7 \\ \hline \multirow{2}{*}{Hydrogen} & \multirow{2}{*}{Fuel cell (PEMFC) + battery} & [PERSON] & 1 & 5 & 8 \\ \cline{3-6}  & & [PERSON] & 2 & 1 & 2 & 5 \\ \cline{3-6}  & & [PERSON] & 2 & 1 & 2 & 5 \\ \hline \multirow{8}{*}{Bodiesel} & \multirow{2}{*}{Mechanical propulsion} & 1 st gen. & 5 & 5 & 2 & 12 \\ \cline{3-6}  & & 2 nd gen. & 5 & 5 & 1 & 11 \\ \cline{3-6}  & & Green & 5 & 5 & 1 & 11 \\ \cline{3-6}  & & 1 st gen. & 5 & 5 & 2 & 12 \\ \cline{3-6}  & & 2 nd gen. & 5 & 5 & 1 & 11 \\ \cline{3-6}  & & Green & 5 & 5 & 1 & 11 \\ \cline{3-6}  & & Green & 5 & 5 & 1 & 11 \\ \cline{3-6}  & & 1 st gen. & **4** & 3 & 3 & 10 \\ \cline{3-6}  & & 2 nd gen. & **4** & 3 & 2 & 9 \\ \hline \multirow{8}{*}{Methanol} & \multirow{2}{*}{Mechanical propulsion} & Grey & 5 & 5 & 4 & 14 \\ \cline{3-6}  & & Blue & 5 & 5 & 2 & 12 \\ \cline{3-6}  & & Blue & 5 & 5 & 2 & 12 \\ \cline{3-6}  & & Green & 5 & 5 & 2 & 12 \\ \cline{3-6}  & & Green & **4** & 3 & 3 & 10 \\ \cline{3-6}  & & Green & **4** & 3 & 3 & 10 \\ \hline \multirow{8}{*}{LNG} & \multirow{2}{*}{Mechanical propulsion} & Grey & 5 & 4 & 1 & 10 \\ \cline{3-6}  & & Blue & 5 & 4 & 3 & 12 \\ \cline{3-6}  & & Green & **4** & 3 & 1 & 9 \\ \cline{3-6}  & & Blue & 5 & 3 & 3 & 11 \\ \cline{3-6}  & & Green & **5** & 3 & 2 & 10 \\ \cline{3-6}  & & Grey & 3 & 1 & 1 & 5 \\ \cline{3-6}  & & Blue & 3 & 1 & 4 & 8 \\ \cline{3-6}  & & Green & 3 & 1 & 3 & 7 \\ \hline \multirow{8}{*}{Electricity} & \multirow{2}{*}{Battery} & Grey & 5 & 5 & 11 \\ \cline{3-6}  & & Blue & 5 & 5 & 11 \\ \cline{3-6}  & & Green & 5 & 5 & 11 \\ \cline{3-6}  & & Green & 1 & 5 & 5 & 11 \\ \hline \hline \end{tabular} Note: \({}^{1}\) Bio-methanol fuel cost is considered as blue methanol fuel cost; \({}^{2}\) E-methanol fuel cost is considered as green methanol fuel cost; \({}^{3}\) bio-LNG fuel cost is considered as blue LNG fuel cost; \({}^{3}\) E-methanol fuel cost is considered as green LNG fuel cost.  
\end{table} 
Table 13: Rating numbers for economic assessment. Table 13 presents a quantitative analysis of the economic benefit, where higher values indicate better economic performance. Fuel cell systems using hydrogen and ammonia rank lowest in both CapEx and OpEx. ICE remains economically viable for both mechanical and electric propulsion. However, the ICE-battery hybrid ranks lower than single-use ICE or battery systems. Alternative fuels like ammonia and methanol show strong economic value across most systems.