Modular electrochemical system

A containerised modular electrochemical cell system 1 is described. The system comprises: a housing 2 and a plurality of electrochemical stacks 10 removably mounted within said housing, where each stack comprises one or more electrochemical cells. The cells are arranged in side-by-side relation to form said stack. Each stack comprises one or more fluid input(s) for receiving feedstock and one or more product output(s). Two or more stacks form a string 100, so that the housing 2 has therein one or more strings of stacks 100 and a power source operably connected to each string. The stacks of each string are electrically connected in series and each string comprises at least one feedstock inlet fluidly coupled to the input(s) of the stack(s). Similarly, at least one product outlet is also fluidly coupled to each of the output(s) of the stack(s). The system further comprises: means for distributing feedstock between the feedstock inlets; flow regulation disposed in said feedstock inlet(s) and/or said outlet(s) of each stack, where said flow regulation is being configured to selectively open and close the respective inlet(s) and/or outlet(s). Computer-implemented power source control is also used to independently control the power supplied to each string of electrochemical cells. Spent electrolyte may also be circulated for reuse and the cells may comprise an AEM.