How much hydrogen is required to run a 65Kw fuel cell at full capacity?

Question

So if I have 2 liters of hydrogen I could run a 60% efficient 65kwh generator off it for an hour

Answer 1

This would depend on the fuel cell and what current you are running it at.  Also it would depend on the membrane resistance.  If you have a polarization curve to go off of you can figure it out.

At full capacity?  If you run a fuel cell at maximum current it will start to destroy itself.  You need to find the maximum current before the it enters the mass transfer region.

Edited

What amperage are you getting at "full capacity"?

Edit #2

O.K., that is not going to happen.  A 65500W FC will have a lot more current than 5-7A.

Lets say with a 65kW FC operating at 300A and 60% efficiency it will take 15760 L/hr or 1.42 kg/hr.

Answer 2

It depends on efficiency.

If you run a 60% efficient, 65 Kw cell for an hour it would require 108.3KwH of Hydrogen or 370,000 BTUs of hydrogen. That is the same energy as about 3 gallons of gasoline.

Here's a formula for calculating the amount of hydrogen required for a fuel cell for an hour.

P = Electricity produced (in KWH)

E = Efficiency (ie. 0.5, 0.6, etc.)

(P / E) 3412 = BTUs of Hydrogen required per hour

Hope this helps