Application and Analysis of Solid Oxide Fuel Cells in Ship Energy Systems

Abstract

This study identifies and analyses the overall energy consumption required for converting LNG (liquefied natural gas) from liquid to gaseous state in high pressure vaporizers at various cargo discharge rates on a liquid natural gas regasification vessel (LNGRV). The actual measured data were collected on an available vessel, to calculate the overall energy consumption of converting natural gas from liquid to gaseous state by three built-in turbo generators. Next, the study considers their replacement with the newest innovative technology including three solid oxide fuel cell (SOFC) power plants of the same power. This paper provides a simplified analysis of the proposed implementation of the SOFC power plant which was performed for the first time in the existing literature. The results show a significant increase in the achievable electrical efficiency of 40.6%, with respect to 32.9% of a system with turbo generators. The research has also shown that waste heat from the SOFCs can be used to produce thermal energy, resulting in further savings of 2.6% in natural gas consumption. Future research could be done on other regasification terminals in the world, which use different main propulsion technology, using an open, closed or combined cycle during the regasification operations.

Representative application of LNG-fuelled ships: a critical overview on potential ghg emission reductions and economic benefits

“…LNG-fueled transportation systems use BOG reliquefaction process to maintain storage tank temperature and limit methane leakage [71]. Natural gas is lighter than air, and if it leaks, it disperses into the atmosphere.…”

Critical Overview and Challenge of Representative LNG-Fuelled Ships on Potential GHG Emission Reduction

“…This release of unburned fuel that escapes into the atmosphere is referred to as methane slip. To minimize this leakage, the BOG reliquefaction procedure is employed in LNG-powered transportation systems to regulate the temperature of storage tanks 76,77) . The cause of methane slip is usually attributed to two factors: the presence of dead volume, which can manifest as gaps between the components of the cylinder unit, and incomplete combustion, which can occur in the coldest regions of the combustion chamber when the engine is running 78) .…”

Impact of carbon pricing on the cruise ship energy systems optimal configuration

“…In the investigated cruise ship energy system, the load allocation (sharing) between the system components in each discrete operating point of the considered operating profile takes place according to the following procedure:  The energy systems components are considered to operate with the following sequence: first, the FCs will be used till they operate between 70% and 90% of their nominal power in order to maintain their high overall efficiency [52]; in subsequence, the DF generator sets will be used till to operate at 90% of their nominal power and finally, the diesel sets will be used till to operate at 90% of their nominal power.  For solutions that include components of different size, it is assumed that first the components of the smaller power will be operated (each one operating up to 90% of their nominal power) and then the components of the larger size (also each one operating up to 90% of their nominal power) till the total power demand is covered.…”