FEASIBILITY ANALYSIS OF PHOTOBIOLOGICAL HYDROGEN-PRODUCTION

Photobiological production of hydrogen from water (biophotolysis) requ ires efficient biological converters, microalgae, and low cost photobi oreactors. Microalgal strains must be developed that exhibit high hydr ogen production rates and photosynthetic efficiencies in dense culture s at full solar intensities. The photobioreactor must expose the Hz pr oducing cultures to sunlight, while allowing recovery of the gas. A pr eliminary analysis is presented of a two stage process in which microa lgae are cultivated in large open ponds to produce a high carbohydrate biomass that then produces hydrogen in tubular photobioreactors. Phot obioreactors constructed of inexpensive, commercially available, glass tubes are proposed for such applications. Photobiological hydrogen pr oduction requires long-term research and development. However it could be of lower cost than systems based on electrolysis of water using ph otovoltaic electricity-the current system of choice for solar hydrogen production. (C) 1997 International Association for Hydrogen Energy.