Here are the basics of electricity generation–it must provide either base power or on-demand power, and it cannot be stored. Base power today is provided mostly by nuclear and coal plants and some hydroelectric. On-demand power is provided mostly by natural gas driven utilities. In other words, an energy source must provide power either all the time or whenever demand spikes up. WIND AND SOLAR PROVIDE NEITHER ONE! Read the short article that illustrates the problem in Germany, a real life test case of wind and solar drawbacks.