Described embodiments include a system and a method. A system includes at least two individually controllable electrochemical cells configured to output electric power. Each individually controllable cell includes an electrolyte, and a first working electrode configured to transfer electrons to or from the electrolyte. Each individually controllable cell includes a second working electrode configured to transfer electrons to or from the electrolyte. Each individually controllable cell includes a gating electrode spaced-apart from the second working electrode and configured if biased relative to the second working electrode to modify an electric charge, field, or potential in the space between the electrolyte and the second working electrode. The system includes a control circuit coupled to apply a respective biasing signal to each gating electrode of each controllable cell of the at least two controllable cells.