Fuel cell generators ranging from subkilowatt portable power units to multimegawatt stationary power plants are emerging to deliver clean and efficient power using a large variety of gaseous and liquid fuels. This new technology is suitable for producing heat and power for residential, commercial, and industrial customers. The fuel cells produce electricity without combustion and use very few moving parts, typically limited to air blowers, and fuel and/or water pumps. Because of high fuel conversion efficiency, combined heat and power generation flexibility, friendly siting characteristics, negligible environmental emissions, and lower carbon dioxide emissions, fuel cells are considered at the top of the desirable technologies for a broad spectrum of power generation applications. This paper discusses different fuel cell technologies, the various applications, and reviews their commercialization considerations and status.