Self-consumption solar kit. Image: Styleuneed.de Shutterstock

Should we install a battery in our solar photovoltaic system? This is a question we all need to ask ourselves when purchasing a solar PV system for our homes.

Energy storage technologies have been around for decades. Batteries for storing the energy produced in solar photovoltaic systems are relatively new to the market.

There are many advantages guaranteed by solar batteries, such as economic benefit, but on the contrary they have a big disadvantage, their price is still very high!

Is it worth investing in solar batteries?

When batteries are installed for energy storage in a solar photovoltaic system, we can store the extra energy produced by the solar panels that is not consumed, instead of sending it to the grid.

With solar batteries, the use of electricity produced by the photovoltaic system is maximized. This stored electricity is that produced during peak production that is not used in the house, so this excess is stored and can be used later!

Let us remember that when the market for the production of electricity for self-consumption appeared, the States initially financed with great incentives for customers to invest in photovoltaic panels. Incentives that included payment based on MW sent to the power grid, as well as state incentives to invest in these systems.

But over time these incentives have been reduced and currently it is not worth sending electricity to the grid to collect it. Now, instead of sending it to the grid, the electricity is stored in solar batteries for later consumption.

Self-consumption batteries
Self-consumption batteries. Image: Jacob_09 Shutterstock

Benefits of investing in solar batteries.

Investing in an energy storage system has more advantages than disadvantages, especially when it comes to photovoltaic solar energy. It should also be taken into account that the benefits depend on the type of photovoltaic system installed, whether it is connected to the electricity grid or not.

It serves as a reserve.

If the solar photovoltaic system is connected to the electricity grid, it will produce energy during the day which will be consumed by household appliances. Any excess energy is sent to the grid, so some of the electricity is “thrown away”.

With a solar battery, this does not happen. Electricity accumulated during the day can be used at night, or as a supplement at times when production cannot be matched.

Energy independence.

Sunlight is only available during the day, that is, when we are not at home. Since most of us use more energy at night. With a solar battery, we will store the excess electricity for later use.

Another advantage is that we save on the electricity bill, because the electricity consumed from the network will be less at night, since we use the electricity accumulated during the day in the batteries.

Helps reduce the ecological footprint.

Fossil fuels are the main source of electricity, so by switching to solar batteries we will reduce the need to use grid electricity. This reduces carbon dioxide emissions.

Part of the virtual network.

Over the past 100 years, power grids have changed a lot. If one thinks of the current electricity grid, it is obsolete.

By installing solar batteries, we promote innovation, by investing in the smart grid, where we can have more information and be more efficient.

In addition, having solar batteries allows consumers to store energy for themselves, but also to produce and distribute their own energy to the grid.

Independence from the electricity network.

Choosing a system with solar batteries allows you to be self-sufficient in terms of energy. Because you no longer consume 100% of the electricity grid at night, but only the batteries, and only in extreme cases you may need to consume electricity from the grid.

In addition, the development of batteries increasingly ensures greater storage capacity. There are even batteries that allow us to consume ourselves for several days (2 to 3 consecutive days without sun).

Disadvantages of investing in solar batteries.

Like everything else, relying on solar batteries for a photovoltaic system also has its drawbacks.

High cost.

Perhaps the main reason why few choose to install solar batteries in their photovoltaic systems.

As solar battery technology is still in full development, to ensure greater storage capacity and greater reliability, they remain expensive and can cost as much as the entire photovoltaic system (panels, inverters, power optimizers).

Before opting for this solution, the ideal is to see the cost-benefit ratio of investing in batteries. This way you will know if the investment is worth it.

It is true that the costs have fallen, and every month there is news in this area, but it is not yet at “desirable” values. It is believed that in a few more years solar batteries for photovoltaic systems will reach values ​​that will quickly pay off the investment. Although this market is very active and can evolve in a few months, some are already anticipating and talking about a boom in residential storage.

Complexity of installation.

Installing a solar battery system increases the complexity of your solar PV system. This means that more can go wrong, from the design to the installation and operation of solar batteries.

It is therefore essential that during the installation phase, the battery system is correctly sized for the needs, as well as the other installations to be carried out (cables, switches, devices, etc.).

No more maintenance.

Photovoltaic solar panels are easy to maintain, but adding a solar battery system will increase the maintenance of the entire system. However, this maintenance depends directly on the type of batteries installed.

If we think of sealed lead-acid deep cycle batteries, the water levels should be checked periodically and the terminals should be kept clean.

Battery chemicals are dangerous and corrosive, so care should be taken during maintenance.

If we opt for lithium-ion batteries, they are easier to maintain.

Lifetime.

The useful life of a battery will depend on the type of battery to be used and its discharge capacity.

Sealed lead-acid batteries can only be discharged up to 50% of their capacity, more than that shortens the life of the batteries.

While lithium-ion batteries can discharge up to 80%!

It should also be noted that during the lifetime of the solar photovoltaic system (between 20 and 25 years), you may need to replace the solar batteries at least once.