Hydrogen electrolyzer output pressure flow

This is for pressurised hydrogen storage number crunching. I have a question about the pressure and flow at the hydrogen output of an industrial size alkaline water electrolyzer. These electrolyzers are rated as hydrogen Nm3/hr and output pressure. So lets say the electrolyzer in question is rated at 15 Nm3/hr and output of 8 atm. Meaning it creates $15~\mathrm{m^3}$ of hydrogen at 1 atm at 68 °F (20 °C) every hour and has a pressure of 8 atm at the electrolyzer hydrogen output. 


Now my question is if there is a back pressure of 8 atm at the output ($\ce{8atm <=> 8atm}$) is there no flow or would there be a flow of $1.875~\mathrm{m^3}$ ($15~\mathrm{m^3}$ at 8 atm) according to the combined gas law?


