Are you really that stupid? It takes time to generate power.
That's not what my physics teacher told me.
So you think power companies just dial a number and thats how much power they get.
The reality is nothing like that sorry (I am truly sorry to bring you back down to reality). It takes time to mine the coal, it takes time to mine the uranium, it takes time to build the solar cells, wind turbines, etc.
he tells me that power is generated based on possible peak demand regardless of how much power is actually used
Grid energy storage must have come a long way since I last looked.
Firstly you still have to generate the power to put into storage. The other thing is there is a "shelf-life" with power storage (i.e power leakage). There is also a energy cost in storing and retrieving that energy. Again we simply don't have the technology to make long term power storage viable.
Thirdly unfortunately because it takes time to generate the power needed at peak demand, power is generated ahead of time. Power companies estimate how much power is going to be used in 6 months time, and build the infrastructure accordingly. A perfect example of this is solar. Power needed at night is generated during the day when the sun is shining.