Proton Exchange Membrane or PEM Fuel Cells are considered to be the most versatile type of fuel cells currently in production. They produce the most power for a given weight or volume of fuel cell. Because they are lightweight, have such high power-density, and cold-start capability, they qualify for many applications, such as stationary combined-heat-power, transport, portable power and even applications in space.
Fuel Cells Comparison – Image courtesy of Nedstack Fuel Cell Technology BV
Pure hydrogen-powered PEM Fuel Cells emit zero particulate matter, SOx or NOx, zero CO or CO2. They have long lifetimes (>20,000 hours) before refurbishment is required and they have a high power density.
Their low operation temperature makes them ideal for operation on ships, as well as being a proven technology with a strong track record in a large variety of applications. (From Nedstack Fuel Cell Technology BV)