Isn't this really the core problem that needs to be solved in any discussion of power? We have plenty of sources for generating power, but we have very few effective ways to store power for use later. The entire system is designed to support peak loads and generate power on demand, rather than storing potential energy in some way so we can pull it out when need it. Isn't that really the core problem that needs solving? I keep visualizing two huge spheres connected with a tube, and a turbine in the tube. When the sun is out, power is used to suck the air our of one sphere, creating a vacuum. When we need to pull that stored potential energy back out of the sphere, you release the air back into the other sphere (which is now the vacuum), spinning the turbine, and generating power. (Using solar power to create the vacuum means it doesn't matter what it costs, or how efficient it is, as long as the power to run the compressor motor does not exceed the power generated by the solar panels.) So: Isn't STORAGE the problem? Not generating capacity? Since the power into the grid has to equal the power out, something controllable is necessary.