Fuel cells have unique attributes that are attractive to automotive and electricity consumers, and also to automotive and electricity companies. These attributes include quiet and responsive operation, high efficiency, low fuel cycle emissions of criteria pollutants and greenhouse gases, and diversity of fuel supply. These features are highly valued in certain market niches and segments, and there are no obvious barriers to fuel cells' entry into the marketplace. Furthermore, three trends serve to reinforce the attractiveness of fuel cells: motor vehicles transitioning from mechanical and hydraulic systems to electrification, electricity generating moving toward distributed generation, and continuing international commitments to reduce greenhouse gas emissions and the environmental footprint of industrial products. However, despite great improvements in fuel cell power density over the past decade, and demonstration of promising performance, both stationary and automotive fuel cell systems face critical remaining challenges. These include primarily cost reduction, achievement of fuel cell system durability targets, development of efficient and low cost fuel reformers, and development of hydrogen storage systems for vehicles that are inexpensive, lightweight, compact, safe, and quick to refuel.