Secondly, qualitatively it should be obvious that the time taken to achieve the desired non-equilibrium steady state is importantif the reaction must be run for a long period, during which time 3 is consumed continuously, before the desired steady state is achieved, the system is chemically extremely inefficient. Overall, the distribution of species within the network and the time taken to achieve steady state are a function of the reaction rates and equilibrium constants, as well as the steady state concentrations of the species involved in the coupled reaction (c.f. eq. 1, box 1), all of which are potential routes for optimization.