Sorry, that is all incorrect.
I’d be happy to explain, but you can research it yourself...and it’s late.
Funny but I have several friends working for Com Ed here in Illinois and they say exactly that. Electricity is over produced at night. In fact the state of Illinois building and several others in Chicago’s loop create ice at night for air conditioning during the day to use the spare night time electricity.
Gas has become very popular recently because it can be turned up and down easily. So many smaller or older coal and Nuclear plants are being decommissioned and replaced with Gas.
While Gas is cheap this works. But its expected that Nat Gas will become more expensive as time goes on. So many of the larger coal and Nuclear plants will still produce the bulk of the power and leave Nat Gas to handle peaks.