Abstract: The present invention provides a distributed energy storage system, and applications thereof. In an embodiment, the distributed energy storage system includes power units, wherein each power unit has a multi-cell battery; a battery manager that monitors battery cell voltages and temperatures; and a controller. The controller provides a first control signal that causes the power unit to store energy in the battery and a second control signal that causes the power unit to generate an alternating current. A server in communication with each of the power units stores data collected from the power units about the batteries and analyzes the data to determine how much available energy is stored in the batteries that can be used to alter a load demand of a power network. In an embodiment, the batteries are lithium ion batteries capable of storing at least ten kilowatthours of energy.