Q. Solar panels are not worth the cost because they don’t work when it’s cloudy or at night. ?

Ans-> Solar power works even in cold or cloudy places, and new tools are allowing us to use it even when the sun goes down!
Because of the way the technology works, solar panels are just as effective—and usually more effective— in cooler temperatures as in hot ones. And while it’s true that clouds can affect the efficiency of solar panels, they can still produce enough power to be viable sources of electricity. Germany, for example, is a country that is not particularly warm or sunny, but is nevertheless the world leader in solar energy, generating more electricity with solar than nuclear power in July 2015.

Reference : climaterealityproject

Q. How Solar Panels Work ?

Ans: