Coupled Transient Operation and Emission Analysis of a Natural Gas-fueled SOFC-Battery Hybrid Demonstrator for Maritime Application

Abstract

Recent demonstrations of commercial stationary natural gas-fed Solid Oxide Fuel Cell (SOFC) Systems have successfully demonstrated LHV to AC electrical efficiency values well above 60% [1,2]. This represents a highly attractive alternative to conventional Diesel- or LNG-fueled gensets of seagoing vessels, as the utilization of SOFC technology can both significantly reduce CO2 emissions and almost entirely avoid combustion byproducts such as nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM) as well as methane slip. However, there are presently no such gensets demonstrated in a relevant power class and overall uncertainty regarding applicability, transient capability, genset sizing and emission reduction potential remains. The recently completed project Nautilus set its objective to close this research gap by developing and testing a novel maritime genset, consisting of LNG-fueled SOFC modules coupled with battery sets to enable reliable load-following while operating at overall high conversion efficiencies. Apart from marine component qualifications such as ship motion inclination testing of SOFC modules [3] and laboratory validation of energy management systems (EMS) [4], one of the core objectives of the Nautilus project consisted of a land-based demonstration of the proposed hybrid SOFC-battery genset to emulate ship-like operating conditions. This contribution aims to give an overview on the core demonstrator results, which include steady-state and transient testing of the SOFC module itself as well as battery-coupled operation in load-following mode of scaled-down real cruise ship profiles for both hotel and propulsive load. During all relevant operating conditions, CO2 and non-CO2 emissions of the SOFC module exhaust were measured and are compared to conventional genset data.