In order to create power, several systems must work together to provide the required electrical output. A typical system would consist of an electrical load (such as a house, or an electric motor), a fuel cell and a fuel processor.
Let's take the case of a fuel-cell-powered car. When you step on the gas (hydrogen) pedal, several things happen at about the same time:
- The electric motor controller starts supplying more current to the electric motor, and the electric motor generates more torque.
- In the fuel cell, more hydrogen is reacted, producing more electrons, which make their way through the electric motor and controller, keeping up with the increased power demand.
- The fuel processor starts pumping more methanol though its system, which creates more hydrogen. Another pump increases the flow of hydrogen going to the fuel cell.
A similar sequence of events happens in your house when you suddenly increase the electrical demand. For instance, when your air conditioning turns on, the power output of the fuel cell has to increase quickly, or else the lights will dim until the fuel cell can catch up with the demand.