APC 400kW1MW User Manual download pdf (Page 16)

sulfur must still be removed from the fuel. The operating temperature also allows for the use of

moderately priced high-temperature materials [17, p. 50; 18, p. 18].

PAFCs are mostly applied to stationary power generation. They were the first fuel cell

commercially available and have the longest record of all the fuel cells types with over 300

systems installed in over 15 countries. Most of these installations are located in Japan, and the

US. Individual units have operated up to 65,000 hours with an average availability greater than

95%. One characteristic of PAFCs that has made them successful is their ability to quickly

respond to changing loads [17, p. 50].

Beginning in 1991, the only stationary fuel cell commercially available for several years

was the UTC Power PC25C, which was a PAFC able to generate 200 kilowatts (kW) of power

[19]. However, from the years 2002 to 2004, manufacturer and developers lost interest in

PAFCs and actually stopped production. One reason their interest decreased was concerns

that the cost of PAFCs would be inherently too large in comparison to other fuel cell

technologies being developed. Another reason was due to the limited potential for higher

electric generation efficiencies that was needed for widespread use of distributed generation

(DG) applications. And lastly, manufacturers and developers had concerns with the reliability

and the life of the fuel cell’s electrolyte [17, p. 50].

Because other fuel cell technologies had yet to demonstrate competitive costs and the

ability to perform consistently, the interest to develop and manufacture PAFCs was rejuvenated

in 2004. There was also an increase in interest from specific niche-markets. where high

reliability is required and in regions where electricity prices are high and natural gas prices are

low. This niche-market had a power requirement range between 100 and 1000kW [17, p. 50;

20, p. 5-12].

Since the new interest for PAFCs within the last couple of years, the

developer/manufacturer UTC Power has produced a 400kW PAFC. UTC’s PureCell 400 Model

is able to reach electrical generation efficiencies of 40%, a stack life of 10 years, and an

installed cost around $2,500/kW, not including government subsidies [21, p. 4]. UTC Power

was able to decrease the capital cost from previous models with the development of less

expensive materials, higher power densities, and optimization of stack/system size [17, p. 50].

Favored applications for PAFCs are for the commercial and small industrial sectors.

PAFCs are suitable for CHP with applications of at least 100kW, which is typical for a medium to

large commercial building [17, p. 50].

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APC 400kW1MW User Manual Page 16