There are two key factors that affect the cost estimation. These are:

1) Cost of the hydrogen storage tank and whether it is Type-II tank or Type-IV tank.

2) Economies of scale. That is to say, the cost will go down as more units are produced.

I've attached a cost report which will help you understand how to calculate the cost based on the aforementioned factors.

Hope you find this helpful and good luck!

Thanks for your response Dr.Yehia. I will go through the report.

Very interesting report Yehia F. Khalil , thanks for the share

Interesting question, I would recommend the National Hydrogen Road-map report from CSIRO-Australia. Useful information on P 26-34.

https://www.csiro.au/en/Do-business/Futures/Reports/Hydrogen-Roadmap

Thank you Dia Milani