Apologies. The needs depend on the various start & end points of the grid. At home for example you would need smart meters that can read your current consumption & (and potential production) and send that data into the system. Our old electricity grids were sort of static and one way, with power plants running a constant amount of power through to our end points. See Smart Grids on Wikipedia for an entry point and you can also find various videos on that topic, one being even in the article. Basically at every point of generation, consumption & distribution you want devices like this so that we end up with an intelligent network of data points that can eventually automatically distribute power to and from where it is made & needed, especially in the context of variable power generation of renewables, but also our variable power consumption based on human & socioeconomic behavior.