Very good explanation of a constantly overlooked problem. <br><br>The only comment I have is that wind mills are not fundamentally unusable for stabilizing the power grid. The problem is that most wind mills are (as you mentioned) nowadays connected to the net with power electronics to generate the right frequency. If you were to connect them with a synchronous generator, you wouldn't have this problem. Downside is that this drastically lowers the efficiency of the windmill.