Standalone PV-diesel system vs. PV-H2 system: An economic analysis

Hydrogen as a long-term storage medium in photovoltaic systems has been a subject of interest in recent years. Such a system uses an electrolyser – H2 storage – fuel cell combination along with battery as short-term storage to minimize the loss of load probability. Conventionally, the same goal is achieved including a diesel generator (DG) in the photovoltaic (PV) systems. In present work, an economic comparison is carried out between DG based system and various possible configurations of H2 based systems suitable for standalone application in the range of 5 kW. Both the systems are compared with the help of boundary curve obtained from life cycle cost analysis and excess energy available in the PV-DG system. Boundary curve enables in determining cost-effective system for a site, specified by on-site fuel cost including transportation cost and seasonal solar energy difference. It is found, a system with unitized regenerative fuel cell (URFC) and metal hydride storage offers most cost-effective solution. Further, the scope of the PV-H2 system is enhanced if the salvage value of the fuel cell is considered. With steeply rising fossil fuel prices and developments in H2 technology, globally more regions will be cost-effective for PV-H2 systems.

► Comparison between PV-DG and PV-H2 systems based on life cycle cost analysis.
► Sites are classified based on seasonal solar energy difference and on-site diesel cost.
► Sites with less seasonal variation is suitable for PV-DG and vice-versa.
► PV-H2 systems with URFC and metal hydride storage are a cost-effective option.