There is a variety of fuel cell technologies suited for different applications.

Most well-known are the so called polymer electrolyte membrane (PEM) fuel cells:

• The conventional low temperature PEM fuel cell (LT-PEM) operating with pure hydrogen offers a high cell energy density. However, pure hydrogen is not always available and is difficult to store especially due to its low energy density per unit volume. Using reformate as a fuel instead of hydrogen (LT-PEM with reformate), the cell power density is still high, but the gas has to be purified, which increases cost and reduces reliability. 

• High temperature PEM fuel cells (HT-PEM) show good performance and run independent of humidification. HT-PEM fuel cells can be operated without gas cleaning under reformate and offer the opportunity for a simple and reliable fuel cell system.

• Direct methanol fuel cells can be fueled with methanol instead of hydrogen. However, the energy density of this fuel cell type is low as is reliability, and the costs are high.
  
  

In addition to PEM fuel cells, there are other technologies available, mainly alkaline fuel cells for aerospace applications, and phosphoric acid, molten carbonate, and solid oxide fuel cells for large stationary applications. Depending on the specific needs of the application, one may select from a variety of different fuel cell technologies.  Some of these fuel cell types work well in stationary power generation plants. Others are better suited for portable electronics, remote & back-up power, auxiliary and residential power or for automotive propulsion.