If you have cells with a lower operating temperature, this reforming process has to be carried out outside the cell stack, which means the system is not only more complex and costly, but also has considerably lower efficiency. Graphic representation of a Hot Module fuel cell power plant, including peripheral systems. There is little scope for reducing costs through economies of scale. Without the need for a reforming plant, the partners looked to see whether further simplifications could be made. They came up with the idea of the hot module, in which many of the functions traditionally performed by ancillary equipment are integrated within the fuel cell vessel.
Fuel gas goes in one end and electricity comes out the other.
The entire plant fits on the back of a lorry. Oxygen is supplied from air taken directly into the cell stack. The temperature is low enough that harmful oxides of nitrogen are not formed as the air is heated. Each cell produces a little less than one kilowatt. So if you stack 200 cells you will get an output of almost 200 kilowatts.