Maritime transport is among the leading sources of greenhouse gases and pollutants which are estimated to cause 50,000 premature annual deaths and €58 billion annual cost to the society in the EU. With the International Maritime Organization (IMO) regulations coming in force, marine transport needs new energy solutions for emissions reduction. Passenger ships are the most affected as they have growing pressure from their customers and habitants near ports for a clean environment. To address these challenges, this project aims at developing, evaluating and validating a highly efficient and dynamic integrated marine energy system fuelled by Liquefied Natural Gas (LNG) for long-haul passenger ships. This energy system, responsible to cater for all heat & power needs of a vessel, consists of a Solid Oxide Fuel Cell (SOFC)-battery hybrid genset with coupling with the existing Internal Combustion Engine (ICE) based generators and gradually replacing these ICEs. The project will develop and deliver a complete process design and digital demonstrator of a fully integrated on-board energy system of a size between 5 and 60 MW for two types of cruise ships: 1000 and 5000+ passenger vessels. A physical proof-of-concept (PoC 30 kWe SOFC+battery) as well as a modularized functional demonstrator (60 kWe SOFC+battery) of the hybrid genset will be developed and operated to validate the design and operation strategies. The digital design and the physical demonstrator will be evaluated against the marine safety regulations. The project brings in a consortium of key actors in maritime passenger transport including ship operators, ship builders, marine engine builder, marine regulatory company, and technology developers supported by research organizations from across the Europe. Together they target to validate this integrated energy system to comply with the IMO targets of 2030 and beyond. Besides, regulatory framework, emission analysis, lifecycle assessment and feasibility of fuel flexibility are addressed.