In this paper, we describe a model for a micro photosynthetic power cell (mu PSC). mu PSC is an electrochemical device which harnesses electrons and protons from the electron transport chains of photosynthesis (in the presence of light), and respiration (in the absence of light) occurring inside an oxygenic photosynthetic organism to generate electricity. mu PSC has been identified as a potential power generating device for low power applications. A one dimensional model for a mu PSC based on mass balances of species in the anode and cathode chambers considering unsteady one dimensional diffusion is developed. The governing equations are solved to obtain the v - i characteristics of a mu PSC device. The unknown parameters in the model are estimated from experimental data. The model with its estimated parameters is validated using test v - i characteristic data. Simulation analysis is performed to understand performance improvement possibilities. Explicit optimization formulations to identify promising device designs are also explored. (C) 2017 Elsevier Ltd. All rights reserved.