Biological photovoltaics, also called biophotovoltaics or BPV, is an energy-generating technology which uses oxygenic photoautotrophic organisms, or fractions thereof, to harvest light energy and produce electrical power.  Biological photovoltaic devices are a type of biological electrochemical system, or microbial fuel cell, and are sometimes also called photo-microbial fuel cells or “living solar cells”.  In a biological photovoltaic system, electrons generated by photolysis of water are transferred to an anode.  A relatively high-potential reaction takes place at the cathode, and the resulting potential difference drives current through an external circuit to do useful work.  It is hoped that using a living organism (which is capable of self-assembly and self-repair) as the light harvesting material, will make biological photovoltaics a cost-effective alternative to synthetic light-energy-transduction technologies such as silicon-based photovoltaics.