A system for converting potential energy into electric power from a mixture of gases, such as atmospheric air, including a particular lesser-density-gas, such as nitrogen, and a particular larger-density-gas, such as oxygen. The system includes a gas-separator at an upper-elevation; a gas-flow-conduit that has a gas-exit-port at a lesser-elevation, where the lesser-elevation is significantly lower than the upper-elevation; and an energy-converter positioned on the gas-flow-conduit. The gas-separator is coupled to the gas-exit-port via the gas-flow-conduit. The gas-separator separates the particular larger-density-gas from the gas mixture. The gas-flow-conduit conducts the separated particular larger-density-gas from the gas-separator via the gas-flow-conduit to the energy-converter; and the energy-converter generates electric power from the conducted separated particular larger-density-gas.