The Naval Research Laboratory (NRL) has developed the benthic microbial fuel cell (BMFC) as a persistent power supply for marine-deployed applications. The BMFC operates on the bottom of marine environments where it oxidizes organic matter residing in sediment with oxygen in overlying water. The NRL BMFC is a maintenance free, non-depleting power supply suitable for a wide range of sensors presently powered by batteries. Unlike batteries however, the NRL BMFC will not deplete owing to constant supply of its fuel and oxidant by environmental processes and constant rejuvenation of its microbial electrode catalysts. For this reason, the NRL BMFC is an ideal power supply for when long duration uninterrupted sensor operation is a must, and for hard to access sensors and high-density sensor arrays where the cost of battery replacement is high.