Solar panels are an increasingly popular option for homeowners and businesses looking to save energy. Since sunlight is needed for the panels to work, you might assume that solar energy would be stored within the panels themselves. The real answer is more complicated. 

What looks like a pretty simple operation from the outside is actually more intricate. Solar panels cannot store sunlight themselves, so they need batteries to help them do the job. In this article, we will investigate how this energy really gets stored.

solar cell

How do solar panels work?

The quick version is that solar panels use a semiconductor material, like silicon, to generate a direct current (DC). This happens through something called the photovoltaic effect.

Under this effect, the DC electric current is created from the exposure of a semiconductor to sunlight. But because an alternating current (AC) is needed to power your home, the energy that is collected needs to first pass through an inverter.

The job of a solar inverter is to convert the current from DC to AC so that it can power your home. Depending on whether your home connects to the electricity grid or is off-the-grid, you will choose to use one of several types of inverters.

Most homeowners with solar panels choose to be connected to the electricity grid. This means that if you have not collected enough solar power, your home will automatically use energy from the grid, called net metering.

In this scenario, a utility meter is installed for the solar panel owner. This records the amount of energy being generated by the panels. If you need to use the electric grid as a supplement, you will receive credits for the amount of stored energy you send back to the grid. 

How is energy stored?

The hero of solar panels is the lithium-ion battery. Solar panels do not have the ability to store sunlight for future use. This is not a problem until direct sunlight becomes unavailable. 

Lithium ions can reverse their chemical reactions. This is what lets them store the solar energy and use it at a later time. When the battery gets fully charged, the stored energy can go back to the grid. When it is depleted, the battery can siphon off the energy being collected to get recharged.  

How much the battery can retain depends on its storage capacity. Lithium’s light weight and relatively low cost make it ideal for solar panels, but you may have to sacrifice in storage. This is what makes being on the electric grid such a draw for people. If the battery cannot store enough, there is a backup.

Benefits of Using a Battery

Solar-plus-storage can be very helpful in certain situations. Obviously, you will not be sending energy back to the grid, which means you miss out on the credit to your electric bill. But it can help save you money possibly, depending on how your utilities are billed.

  • Time-of-use rates fluctuate depending on the time of day. Using solar power strategically during the times when rates are highest will help you save some extra money.
  • If you live in an area that does not have net metering or reduces how much credit you can get from sending energy back to the grid, a battery would save you money. Since you are not paying less on your bill with the credits, you can find those savings with storing solar energy.

Another benefit exists when your home loses power. You will not be able to get power from the electric grid when this happens, but you can get power from your battery storage, at least for the amount of energy it has stored.

 Can Batteries Help Me Go Off-Grid?

If you are looking for a way to completely cut off the electric company, it is possible. However, you cannot get there with a simple lithium-ion battery. These batteries are designed to give you a few hours of energy beyond what you can get from solar, but they are not a long-term solution.

To make this work, you need “balance-of-system” equipment. This varies depending on your individual situation. Your supplier would be able to tell you exactly what you need so that off-the-grid can work for you. 

Battery storage systems are batteries that can hold more energy and dispense it over longer periods of time. Using a less powerful battery would not allow you to be self-sufficient apart from the grid. This system will cost you more, but the benefit is self-reliance and less greenhouse gas emissions.

The solar panel system may work much differently than you assumed. Some think the panels themselves are what allow you to have energy at night, but the system is much more intricate than that. If you have the right set up, you can even cut ties with the utility company.

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