Specification

Alkaline

PEM

SOE

Technology maturity

State of the art

Demonstration

R & D

Cell temperature, ˚C

60 - 80

50 - 80

900 - 1000

Cell pressure, bar

<30

<30

<30

Current density, A/cm²

0.2 - 0.4

0.6 - 2.0

0.3 - 1.0

Cell voltage, V

1.8 - 2.4

1.8 - 2.2

0.95 - 1.3

Power density, W/cm²

Up to 1.0

Up to 4.4

-

Voltage efficiency, %

62 - 82

67 - 82

81 - 86

Specific system energy consumption, kWh/Nm²

4.5 - 7.0

4.5 - 7.5

2.5 - 3.5

Partial load range,%

20 - 40

0 - 10

-

Cell area, m²

<4

<300

-

Hydrogen production, Nm²/hr

<760

<30

-

Stack lifetime, hr

<90,000

<20,000

<40,000

System lifetime, yr

20 - 30

10 - 20

-

Hydrogen purity, %

>99.8

99.999

-

Cold start-up time, min

15

<15

>60