Morning, Noon, and Night: How Solar Power Systems Work throughout the Day

December 2, 2019

As we all know, the sun doesn’t shine during every hour of the day.

So, what does a solar power generation system do after the sun goes down? Does everything simply shut down?

Not quite.

In this week’s blog post, we’re examining the three phases of solar power systems operation as they relate to the natural course of the day. Because of advancements in the technology used to build these highly complex systems, they can ‘intelligently’ make the best use of available electricity at all hours of the day, whether that power comes from the grid or not.

The Morning Hours

When the sun is rising, the photovoltaic (PV) cells begin generating an electrical current. This initiates a signal to the overall power system that electricity from the panels is available.

Electricity produced by the solar panels will almost always take priority over grid-sourced electricity.

However, if more power is required above and beyond what can be produced by the solar power generation system, electricity from the grid will be used. Keep in mind this only pertains to ‘grid-tied’ solar systems—not ‘off-grid’ ones.


Afternoon Operation

As the day wears on, electricity use within the home or business will normally fluctuate. As people leave their homes to go to their jobs or other places, it’s likely that more electricity will be generated by the solar power system than is needed at the time.

When this happens, the extra electricity can either be stored in capacitors (industrial-grade batteries), or it can be sent back to the power company for use by others who are tied into the same power grid.

When electricity is sent ‘upstream’ in this way, the owner of the solar power equipment used to generate it will often receive credits that can be used to offset the cost of the grid-sourced electricity they consume later.

Evening and Nighttime Operation

When the sun sets, the PV cells don’t have any work to do. But, that doesn’t mean that the solar-generated power stored throughout the day simply disappears.

If there is electricity stored in the capacitors mentioned above, that electricity can be used during the evening and nighttime hours, saving the system owner extra money, as evenings tend to be ‘primetime’ energy usage windows.

Once the capacitors have been exhausted of all of their stored power, the system will revert to using grid-sourced electricity.


As you can see, the solar power generation system of today is uniquely designed to make the best use of both solar-generated and grid-sourced electricity.

The results for home and business owners are lower energy bills and higher energy independence—a win-win!

To learn more about how you can start saving money as soon as next month, contact Urban Solar today and inquire about a free energy assessment.