A hydrogen generating system regulates its rate of hydrogen generation by monitoring one or more parameters of the hydrogen generation process and then providing relative movement between the fuel tank and the catalyst chamber so as to increase or decrease the rate of hydrogen generation. In the disclosed embodiments, the catalyst chamber is disposed in a tank containing the fuel. The relative movement provided moves the catalyst chamber toward the fuel solution so as to increase the rate of hydrogen generation and moves the catalyst chamber away from the fuel solution to decrease such generation. Advantageously, such self-regulation can be provided without an external power source and can be varied to meet the requirements of different commercial applications. The overall system can be readily fabricated using commercially available parts.