Fuel cell technology has long promised the dream of quiet, reliable, and clean generation of electricity. Improvements in fuel cell technologies coupled with an increasing need for stand-alone and on-vehicle generation of electrical power are turning many of those dreams into reality.
Shipments of all types of fuel cells tripled between 2011 and 2012 to over 78,000 units. Since 2008, 514.4 MW of fuel cell capacity has been shipped worldwide. Over half of this capacity is based on Proton Exchange Membrane (PEM) technology. PEM technology is perhaps the most versatile fuel cell technology and is particularly suited to smaller applications including the fast growing market for back-up power, domestic power generation, and the rapidly emerging transportation market. PEM technology uses hydrogen for fuel.
The rise of the PEM fuel cell represents a significant opportunity for the manufacturers of hydrogen and of hydrogen generation, purification, compression, storage, and analytical equipment. This opportunity brings with it plenty of challenges.
One challenge that is attracting considerable attention is how best to achieve and certify adequate hydrogen fuel purity. PEM fuel cells use precious metal catalysts. Catalyst activity is harmed by the presence of carbon monoxide (CO) or sulfur compounds in the hydrogen fuel. Thus there is a trade-off between the amount of catalyst, fuel cell output and lifetime, and hydrogen fuel purity. To achieve satisfactory lifetime and performance while controlling fuel cell costs, the emerging ISO standard for hydrogen transportation fuel calls for CO concentration to be less than 200 parts per billion (ppb) and for sulfur concentration to be less than four ppb.
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