The use of renewable energy resources and storage units is increasing in the electrical grids. Most of distributed generation and storage units are connected to the grid via power-electronic converters. In near future the electrical grid will be dominated with the inverters of very fast dynamics. New identification and control problems for the inverter-dominated grids are discussed in this talk. A new data-driven control methodology is introduced to design decentralised and distributed controllers using only frequency response data. It is shown that how this method can be used for current control of parallel grid-connected inverters and distributed primary and secondary control in islanded grids.