Where does conserved electricity go if it is not used?

If i conserve or save electricity, what happens to it if i or somebody else doesn't use it? Shouldn't I try to use all electricity that is provided so it does not go to waste? The cost to run the power plants is the same if i consume 1 kilowat or 10, so why am i charged per kilowat and not a flat rate? Isn't conserving electricity result in the waste of electricity since the saved electricity cannot be stored in mive batteries for later use?