A system includes multiple hybrid energy storage modules (HESMs) configured to accept constant-current DC input power from a main power source. Each HESM has a plurality of outputs configured to sequentially or simultaneously provide both constant-current and constant-voltage output power to multiple loads, the loads comprising steady state, pulsating, or intermittent loads. Each HESM comprises a combined rotating electrical machine-inertial storage module and electro-chemical storage module configured to generate second power that augments or induces first power derived from the main power source, so as to permit constant power draw or constant current draw from the main power source, wherein the output power comprises the first power and the second power.