Here's why:

* Solar panels generate electricity from sunlight. They use photovoltaic cells to convert sunlight into direct current (DC) electricity.

* Without sunlight, there's no energy source for the solar panels to work. They essentially become inactive.

* Solar panels are not batteries. They don't store the electricity they generate.

To use solar energy even when there is no sunlight, you need a battery system:

* Batteries store the electricity generated by solar panels during the day.

* When the sun goes down, the batteries discharge to provide power.

Therefore, the amount of power a solar panel "holds" without sunlight is zero.