Hydrogen gas has proven to be an ideal green fuel. Its use is limited at present due to inefficient and harmful methods of production like steam-methane reformation and coal gasification. Systems that utilize hydrogen as a fuel can be considered practical only with the development of better, cost-efficient methods of its production. This study focuses on efficient mass production of bio-hydrogen (and bio-ethanol as a byproduct) for commercial utilization with a theoretical multiple reactor system. The process involves culturing of modified photosynthetic algae (such as Chlamydomonas reinhardtii) in bioreactors for bio hydrogen production. This process produces some waste algal cells. These can be sent to subsequent reactors for production of bio-ethanol by fermentation. Also, the waste algal cells need to undergo pyrolysis before the fermentation. Hydrogen is produced in this process too. All these factors put together improve the overall yield of the complete process and reduce its cost substantially. Though the model is theoretical, it can be adapted for commercial production of hydrogen. The hydrogen can, in turn, be used as fuel for powering fuel cells which have zero emission and hence, are environment-friendly. © Published under licence by IOP Publishing Ltd.