Fuel cell electric vehicle as a power plant and SOFC as a natural gas reformer: An exergy analysis of different system designs

Abstract

Delft University of Technology, under its “Green Village” programme, has an initiative to build a power plant (car parking lot) based on the fuel cells used in vehicles for motive power. It is a trigeneration system capable of producing electricity, heat, and hydrogen. It comprises three main zones: a hydrogen production zone, a parking zone, and a pump station zone. This study focuses mainly on the hydrogen production zone which assesses four different system designs in two different operation modes of the facility: Car as Power Plant (CaPP) mode, corresponding to the open period of the facility which uses fuel cell electric vehicles (FCEVs) as energy and water producers while parked; and Pump mode, corresponding to the closed period which compresses the hydrogen and pumps to the vehicle’s fuel tank. These system designs differ by the reforming technology: the existing catalytic reformer (CR) and a solid oxide fuel cell operating as reformer (SOFCR); and the option of integrating a carbon capture and storage (CCS).Results reveal that the SOFCR unit significantly reduces the exergy destruction resulting in an improvement of efficiency over 20% in SOFCR-based system designs compared to CR-based system designs in both operation modes. It also mitigates the reduction in system efficiency by integration of a CCS unit, achieving a value of 2% whereas, in CR-based systems, is 7–8%. The SOFCR-based system running in Pump mode achieves a trigeneration efficiency of 60%.