CO is a known fuel cell poison and is a result of using reform liquid fuels. The CO content necessitates fuel clean up which in turn means that use of reform liquid fuels requires much cumbersome systems because of larger and therefore more costly systems. Due to the elevated temperatures in HTPEM, hydrogen with a higher CO concentration can be used without the same negative impacts on the performance. This makes it possible to directly use hydrogen reformate originating from cheap, and easy to handle energy-carriers such as methanol, ethanol, diesel etc.

The HTPEM fuel cell can tolerate up to 3% (30,000ppm) CO and up to 20ppm of sulphur without permanent degradation. In comparison, LTPEM fuel cell normally can tolerate less than 30ppm CO and less than 1 ppm of Sulphur. This is a factor of 1,000 difference in CO tolerance. Because of the high operating temperature, a PrOx reactor is normally not necessary. PrOx reactors are expensive, bulky and significantly lower the system efficiency. The result is that very simple, lightweight and inexpensive reformers can be used to produce hydrogen from a broad range of energy-carriers including the choices listed above.

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