They can't. Price has already been set.

Thats how energy buying goes.

Texas might be the exception, they have a lot of shady instant pricing. But for the rest of us, its quite regulated.

How to heat with solar at night.

Using the solar panels and a glowplug During the day heat some water or rocks in a container as hot as possible. it will give off that heat all night.

Next day the panels do it again.

You can also jeatrocks or water on solar thermal collectors during the day.

Any boy scout knows a rock in the fire wrapped in a cloth in your sleeping bag keeps you warm all night.