The Navy needed a better way to power underwater sensors without using batteries that require constant maintenance. They explored using microbial fuel cells (MFCs) that can generate energy from bacteria in water. However, MFCs produce low voltage and current. Two power management systems were designed to boost the MFC's power output, allowing it to power electronic devices. These systems store energy in a supercapacitor from the MFC and then use it to power external devices. The systems operate autonomously and increased the MFC's input potential from 300mV to 3.3V, and power from microwatts to milliwatts.