Why is current supplied to consumers from generating plants in the form of alternating current?

It is a much more efficient mode of transmitting electricity than direct current.

Current supplied to consumers from generating plants like coal power plant, nuclear power plant, geothermal and others are in form of alternating current instead of direct current because it can be transported easily in a long distance. Also, the alternating current has a wide range of frequency and the amount or energy can be increased or decreased.