At the most basic level, solar panels work by absorbing sunlight and converting it into electricity. However, the real work is done by solar cells, which convert the photons in sunlight to electrons. When sunlight is absorbed by a solar cell, the energy in that sunlight is transferred to electrons in the solar cell, giving them enough energy to free themselves from the solar cell material. A built-in electrical field pulls the electrons in one direction, causing them to flow and creating a current. From there, the electrons are collected by small wires on solar cells, then routed through internal wiring of the solar panel and finally exit through wires on the back of the solar panel.

The electrons continue their journey through the wiring of the solar panel system until they reach an inverter where the electricity from the solar panels is converted to make it identical to the electricity that your power company supplies. The inverter is connected to your electrical panel so the electricity can be routed to where it is needed in order to operate lights, appliances, or other electrical loads in your home. When a solar panel system is “grid-tied” (which most are), any excess energy produced by your solar panels flows back through a meter into the grid. Your meter will measure how much energy you’ve consumed from the utility as well as how much you’ve provided back to the utility.

Cloudy days mean less sunlight which a solar panel can use to generate electricity. So your solar panels will work, but they will produce a lower amount of energy. For example, on a cloudy day, if your solar panels receive half the sunlight that they do on a sunny day, they will produce half the energy they would have on a sunny day.

Cloudy days can also be accompanied by rain or snow. Periodic rain is actually good for your solar panels since it washes off accumulated dust. On the other hand, snow can temporarily block enough sunlight that your solar panels won’t work for a bit. The good news is that snow doesn’t last as long on a solar panel as a traditional roof. A little sunlight will still get through the snow and warm the solar panel, melting the snow.

In any weather situation, the energy generated by solar panels is directly proportional to the amount of sun they receive.

This is why you’ll always want the solar panels to be located where they will receive the most sunlight. Your local weather patterns will influence how much energy a home solar system can generate, but what’s more important is where solar panels are placed on your roof or property. Careful evaluation of shading from nearby trees and other structures is critical to having a good system design and maximizing the return on a home solar investment.

Generally no, your home solar system is designed to monitor the presence of the grid and shut down if it does not detect the grid. This is a safety measure for the utility workers who are working to restore grid power. Here’s why: If your system was still producing electricity and some of that electricity was being exported into the grid while utility workers were fixing power lines or other equipment, they could be shocked.

In order for your home solar system to operate when the grid is down, you’ll need to consider a system which includes home batteries. The primary function of home batteries is to store excess energy generated by your home solar system for use when your home solar isn’t producing as much as you are consuming or the grid is down. Home battery systems also provide two features which are critical in enabling a home solar system to function when the grid is down.

First, a home battery system will include a transfer switch to disconnect your home’s electrical system from the grid if the power goes out (same as if you had a generator). Second, they provide a power source for your home solar system. This power source provides the “grid” that your home solar system needs to operate.

Learn more about home batteries here.