Page 160 - Power Quality in Electrical Systems

142 Chapter Nine

Battery cost vs. capacity
per kW power output
24000
20000
Cost ($) 16000
12000
8000
4000
0
0 10 20 30
Run time (hours)
Figure 9.12 Battery cost versus capacity per kW power
output. Acquisitions cost comparison for fuel cells and lead-
acid batteries in standby power applications. Battery cost-
diagonal shading. Fuel cell cost [9.21].
[© 2004, IEEE, reprinted with permission]

Table 9.1 shows the major types of fuel cells considered for standby
and alternative electric power use. For applications that require frequent
and rapid start-ups, and where hydrogen and air are the available reac-
tants, a polymer-electrolyte membrane fuel cell (PEMFC) is the obvious

TABLE 9.1 Major Types of Fuel Cells. (Advantages vs. Disadvantages) [9.22]
Operating
Electrolyte temp. ( C) Advantages Disadvantages
Polymer- 60–100 ■ Highest power density ■ Relatively expensive
electrolyte ■ Reduced corrosion catalysts required
membrane and electrolyte- ■ High sensitivity to fuel
fuel cell management problems impurities
(PEMFC) ■ Rapid start-up time
Alkaline 90–100 ■ High power density ■ High sensitivity to fuel
fuel cell ■ Demonstrated in impurities
(AFC) space applications ■ Intolerant to CO 2
Phosphoric 175–200 ■ High quality waste ■ Relatively expensive
acid fuel heat (for cogeneration catalysts required
cell (PAFC) applications) ■ Relatively low power
■ Demonstrated long life density
Molten 600–1000 ■ High quality waste heat ■ High temperature enhances
carbonate ■ Inexpensive catalysts corrosion and breakdown
fuel cell ■ Tolerant to fuel of all cell components
(MCFC) impurities ■ Relatively low power density
Solid 600–1000 ■ High quality waste heat ■ High temperature
oxide fuel ■ Inexpensive catalysts enhances corrosion and
cell (SOFC) ■ Tolerant to fuel breakdown of all cell
impurities components
■ Solid electrolyte ■ Sealing of stacks

[© 2004, IEEE, reprinted with permission]