re: Clouds and Night
There are many kinds of energy sources, and all of them have places where they are appropriate, and even profitable.
Solar panels make a lot of sense in hot, sunny climates, where air conditioning is a huge power draw, and one where the greatest need comes when the sun is beating down hardest on a cloudless day. Most people use natural gas or oil for heat at night anyway.
There are places where wind makes sense. Places where tidal, hydroelectric, thermal, and other sources work well.
And of course, conventional and nuclear power have a place, too.
No single solution is, or should be, considered a "universal" solution, forced on areas where they aren't practical.