This paper will investigate optimizing the payback of lithium-ion batteries for passenger vessels. Factors considered regarding the lithium-ion battery technology will include depth of discharge, charge and discharge rates, cycle life, effective cost, effective life cycle cost, and energy density. The cost of shore-side electricity also plays a huge role. Other factors analyzed include the price of diesel and the discount rate. Payback will be analyzed for the three lithium-ion battery chemistries found in the marine sphere: lithium iron phosphate (LFP), lithium nickel manganese cobalt oxide (NMC) and lithium titanium oxide (LTO).
The paper will also investigate the two options for all-electric operation. One is a true " all-electric" without installed diesel engines for backup propulsion power. The other is a plug-in hybrid electric vessel (PHEV) has enough battery power to make zero-emissions crossing but with backup power in the form of diesel gen-sets. The above drivers for payback and specific operational and emergency response requirements for the route will be explored in relationship to this decision.