because solar panels are not a controllable energy source, solar is great until there's a cloud or it's nighttime, coal on the other hand is a controllable energy source. Since we can't effectively store energy we have to be constantly producing enough for the whole population, it's a really hard job!
Did you know that the best way we currently have to store energy are dams?
In most dams you can install a pump to take water and store it higher, then when energy is needed you simply open the turbine.
huh i hadn't heard of this one? I went to a dam last year and that's what the guide told us...