Scenario analysis of a bioethanol fueled hybrid power generation system

Abstract

Regarding most of FC/PV/Battery based hybrid power generation systems, the photovoltaic (PV) power usually dominates the main power supply and the water electrolyzer is used to produce hydrogen. The energy efficiencies of these hybrid power generation (HPG) systems are usually low due to the low conversion efficiency of PV cell and the extra power consumption to hydrogen production. To reduce the electricity demand by the PV system and improve the energy efficiency of hydrogen production unit, a scenario-based design of the HPG system is necessary. This paper proposes an EFC/PV/Battery based hybrid power generation system to meet 24-hour power demand. An ethanol-fueled fuel cell (EFC) power generator not only dominates the main power supply, but also a combination of the stand-alone EtOH-to-H2 processor and PEMFC can ensure higher energy efficiency. A PV system is treated as an auxiliary power generator which can reduce the (bio)ethanol consumption. A backup battery not only stores excess power from PV or EFC, but also it can precisely satisfy the power demand gap. Finally, scenario analysis of the hybrid power generation (HPG) system in regard to the hybrid power dispatch and energy efficiency is addressed. An optimized fuel processing unit using ethanol fuel can produce high-purity hydrogen. The simulation shows that the stand-alone EtOH-to-H2 processor not only guarantee the high energy efficiency, but also it can continuously produce hydrogen if the fuel is enough. According to scenarios for the daily operation of the HPG system, the EFC power dominates the power supply during the night, the PV system dominates the power supply during the day and the backup battery aims to instantly compensate the power gap and store the excess power from PV or EFC. According to the hybrid power dispatch, the distribution of the HPG system efficiency is specified.