Understanding Solar Energy Storage

Every residential solar user knows that while a solar array provides a sustainable way to gain grid independence, a simple system is not enough.

The biggest drawback of switching to solar is that the system does not generate power when the sun doesn’t shine. And while a solar array can help you save big on utility bills, its true potential can only be unlocked when you consider storing solar energy.

That’s why residential solar users need to understand the science and economics behind solar energy storage.

How Is Solar Energy Stored?

Solar panels cannot store solar energy. You need an Energy Storage System (ESS) for storing the solar energy that your PV array produces every day.

Fortunately, there are multiple ways of storing solar energy, including mechanical, thermal, and battery storage. The caveat is that not all three are viable solar energy storage choices for homeowners.

So let’s look at the two most common solar energy storage methods suitable for residential solar users:

Solar Battery

The best and most efficient way to store energy generated by solar panels is with the help of a solar battery.

A solar battery saves all excess energy your solar array produces for future use. It then discharges this energy, converting DC to AC output when needed. Since solar panels produce DC power but all standard household appliances work on AC, you need batteries when you switch to solar.

Solar batteries are versatile. There are many types of solar batteries suitable for all budgets, although the storage capacity and efficiency vary depending on their working mechanism.

Solar Battery

The best and most efficient way to store energy generated by solar panels is with the help of a solar battery.

Lithium-ion Batteries

These batteries have high energy density and can store a lot of power in a small space. Low maintenance with a long life span, Li-ion batteries are some of the most expensive yet highly efficient of the lot.

Lead Acid Batteries

Lead acid batteries are cheap but effective for bare minimum energy storage. But these batteries tend to have a low depth of discharge and must be charged often to meet your residential energy needs. These batteries last for 5 to 10 years on average.

Nickel Cadmium Batteries

Highly durable with little to no maintenance needed, nickel-cadmium batteries are usually better suited for commercial solar panel installations. But if your household energy consumption is high or you have a huge property that you want to run on solar, they are viable options.

The downside to nickel-cadmium batteries is their environmental impact—they are incredibly toxic to recycle.

Flow Batteries

A relatively new addition to solar storage, flow batteries are highly efficient and boast 100% Depth of Discharge (DOD). You can use all the energy that your battery stores when you need to. These batteries have a lifespan of 30 years and require little to no serious maintenance.

The only downside to flow batteries is that they are even more expensive than Li-ion batteries and may not be ideal for homeowners with limited budgets.

Choose a battery that your solar provider recommends and suits your household needs. Solar panel energy storage should give you the best return on your investment possible.

Remember, if you are an off-the-grid solar user or want to gain total energy resilience, solar batteries are the way to go.

Flow Batteries

Local Utility Grid

What if you’re a grid-tied user who only uses solar energy to offset their daily electricity consumption? If your local government has net metering regulations or your utility provider offers Time of Use (ToU) rates, you might not need a battery after all.

Storage of solar power is not needed if your system is tied to the grid. This is because your utility provider will be your storage system. Any excess power you produce will return to the grid, and you can draw power for personal use when your home needs it.

You will still depend on the grid, but you can offset your energy usage if your solar array produces enough power.

Benefits of Storing Solar Energy

Combining your array with energy storage for solar panels will allow you to use solar power even when the sun is not shining. Because weather conditions are never consistent, even in the sunniest of states, storage of solar power is non-negotiable for homeowners relying on solar energy.

Storing solar energy has many advantages:

  • You can maximize the use of the solar energy that your PV panel produces
  • You will have backup power during outages or when your solar panel is not generating enough energy
  • You can reduce your utility bills by mitigating your need for drawing power from the supply grid during peak hours
  • You can gain energy independence partially, if not entirely. At a time when rate gain is a hard reality every homeowner has to consider, being energy resilient can give you peace of mind.
  • You will reduce your overall carbon footprint

Consult your local solar panel company and explore the various options for storing solar energy.

Benefits of Storing Solar Energy

Which Solar Energy Storage Solution Should You Choose?

This depends on your reasons for going solar. Residential solar panel installation comes at a cost, even if you account for federal tax credits and other incentives. Purchasing a battery for storing solar energy will add to your expenses. Fortunately, solar batteries yield great ROI in the long run.

Grid-tied solar panel installation can also help you make significant savings.

The wisest thing you can do is use a solar panel cost calculator. If your overall investment gives you profits, go for solar batteries for storing solar energy. However, if your estimated solar panel needs can be met with net metering or ToU rates, you might not need to invest in a solar energy storage system.