Week 2 Challenge

FUEL CELL TYPE

COMMON ELECTROLYTE

OPERATING TEMPERATURE

TYPICAL STACK SIZE

ELECTRICAL EFFICIENCY (LHV)

APPLICATIONS

ADVANTAGES

Polymer electrolyte membrane (PEM)

Perfluorosulfonic acid

<120°C

<1 kW–100 kW

60%

· Backup power

· Portable power

· Distributed generation

· Transportation

· Specialty vehicles

· Solid electrolyte reduces corrosion and electrolyte management problems

· Low temperature

· Quick start-up and load following

Alkaline (AFC)

Aqueous potassium hydroxide soaked in a porous matrix, or alkaline polymer membrane

<100°C

1–100 kW

60%

· Military

· Space

· Backup power

· Transportation

· Wider range of stable materials allows lower cost components

· Low temperature

· Quick start-up

Phosphoric acid (PAFC)

Phosphoric acid soaked in a porous matrix or imbibed in a polymer membrane

150°–200°C

5–400 kW

40%

· Distributed generation

· Suitable for CHP

· Increased tolerance to fuel impurities

Molten carbonate (MCFC)

Molten lithium, sodium, and/or potassium carbonates, soaked in a porous matrix

600°–700°C

300 kW–3 MW,
300 kW module

50%

· Electric utility

· Distributed generation

· High efficiency

· Fuel flexibility

· Suitable for CHP

· Hybrid/gas turbine cycle