Assessment of Bio-Fuel Options for Solid Oxide Fuel Cell-Based Auxiliary Power Units

It is now illegal in many states to idle heavy-duty trucks to supply the cabin electrical needs of the driver. An alternative approach is the solid oxide fuel cell-based auxiliary power unit (APU), which can produce electrical power with much higher efficiency and lower greenhouse gas emissions. The "standard" APU system includes a fuel reformer, which converts on-board diesel fuel into a hydrogen-rich effluent that is delivered to the anode side of the fuel cell stack. As renewable bio-fuels begin to realize greater market penetration, there is a need to determine which bio-fuel option provides the optimal pathway to economic value and emissions reduction when converted for use in a fuel cell APU system. The results of this study indicate that biodiesel from waste cooking oil may be the optimal bio-fuel option because of its relatively low energy use and greenhouse gas (GHG) emissions, as well as chemical and physical properties that are similar to those of petroleum-based diesel fuel.