Methods and devices are disclosed for electrostatically generating electrical energy in response to state changes of external energy sources. In a simple embodiment, a first diode directs priming current from a first rechargeable battery into a variable capacitor means when the latter means is in a charge desorbed mode (charge absorbing mode). An external energy source switches the variable capacitor means into a charge expelling mode while absorbed charge is trapped in the variable capacitor means. After a predefined increase in voltage is realized, a second diode directs expelled charge from the variable capacitor means to a series circuit composed of a profit-charge storing means (e.g. a second rechargeable battery) and the first rechargeable battery, thereby returning the invested charge back to the donor (the first rechargeable battery) and causing a profit amount of charge to be stored in the profit-charge storing means (the second rechargeable battery). The variable capacitor means may take on many forms including those which switch between their charge absorbing and charge expelling modes in response to thermal agitation. Various forms of nonelectrical energy sources and ways for electrostatically converting their energies into electrical energy are disclosed.