Feasibility study and optimal sizing of H2 storage and PEM fuel cells onboard ships

Abstract

The International Maritime Organization (IMO) established a challenging global strategy in 2023 to reduce greenhouse gas (GHG) emissions from international shipping by 70% by 2040. Achieving these targets necessitates radical actions, including the use of carbon free fuels and hybrid-alternative propulsion systems. The NEREHYDES (Novel hEat REcovery solutions on board of fuel cell equipped vessels for metal HYDridES storage optimal management) national research project aims to optimize the design and management of a hybrid system with hydrogen fuelled Proton Exchange Membrane Fuel Cells (PEMFC) and diesel Internal Combustion Engines (ICE) on board short-travel ferries for zero-emission operation in coastal and harbour areas. The new PEMFC - MH system is designed to operate mostly in harbour, while the traditional ICE operates during navigation in open sea. The study consists of a pre-feasibility analysis for retrofitting an existing ferry by including a PEMFC system. For the hydrogen storage required for the considered travel distances, metal hydrides (MH) storage is employed, allowing for the H2 storage at low pressure and close to room temperature. The study is carried out considering the requirements of two real vessels operating in Sicily (Italy) and their daily travelling routes, aiming to find the optimal sizes for both PEMFC and MH systems, minimizing the overall costs and volumes to properly fit this additional system into the existing ferries. Finally, a preliminary techno-economic and environmental assessment is performed to compare the different solutions.