A Guide to Battery Storage: Does it make sense?

The Irish government’s target of generating 8 GW of power through solar PV by 2030 is an ambitious one. However, across Ireland, the exciting new technology is witnessing a heartening increase in use.

By the summer of 2024, some 94,000 Irish households had undergone a solar installation, an increase of 20,000 from last year. While tens of thousands across the island have found a future-proof way to reduce emissions and save money, installing solar batteries could open an entirely new realm of possibilities.

At WattCharger, we strive to ensure that your sustainable capacity is where it should be. Today, we will be exploring the utility, as well as the benefits of adding a battery to your solar PV panel array.

What is a solar battery?

Essentially, a solar battery serves as a large rechargeable battery, similar to those found in smart phones. As we will learn, the presence of a solar battery in an existing solar PV array allows homeowners an additional level of control over their energy production, as well as the possibility of saving big.

In the absence of a solar battery, the PV system will still work. However, without battery storage, the PV system will automatically draw from the grid during times when solar output is minimal – such as the evening and the morning.

This system, although more sustainable than relying on fossil fuels for energy, is inefficient. Although the sun will provide power when it is out, consumers will find themselves reliant on the grid during off-peak times. Reliant too on the rates charged by your provider.

This is where solar batteries come in.

There are four types of solar batteries. These types are lithium-ion, lead acid, nickel-based, and flow batteries. Due to relatively favourable efficiency and a compact size, most home arrays feature a lithium-ion battery.

Once the powerful Direct Current (DC) is captured by the solar cells, it is fed through an inverter to convert the energy to Alternating Current (AC), which is then used to power the home. When more DC is produced than can be converted, then the excess energy flows to the battery.

Batteries are able to hold the excess energy produced during peak times. As opposed to the traditional model, that only allows your PV array to work when the sun is shining, a battery can hold the excess energy for later.

Though about 2,000 times larger than a phone battery, solar PV batteries have an average capacity of 10 kWh. As such, most home arrays will need several individual batteries to store all of the energy produced by an average panel array, which is about 10 to 15 kWh per day.

A solar battery allows the consumer more independence regarding the use of solar production. In addition to being able to circumvent grid rates by using your own stored energy, it also allows one to store more energy for microgeneration purposes – as over 100,000 dwellings in Ireland have done.

Why do solar batteries make sense?

Since 2022, the Irish government has allowed those who generate power through solar PV to sell excess power back to the grid at a nominal profit. Known as the Clean Export Guarantee, the scheme sees electricity suppliers like SSE Airtricity or Energia remunerate their clients.

With suppliers like Electric Ireland charging rates of €37.67 cents, it’s not difficult to imagine the savings that solar batteries can provide. Seeing as though the same provider offers €21 cents per kWh of exported clean energy, it is not difficult to imagine the savings that could be realised by increasing battery storage capacity.

Participation in net metering programs like this are facilitated by the use of a Smart Meter. These meters manage real-time data to supply the system owner with a snapshot of energy production and usage. Some of these meters are incredibly well-designed. For instance, the EnergiHub App from SSE Airtricity takes into account weather, past prices, and forecasts to automatically siphon excess energy to the grid, as well as store some for later.

In short, the presence of a solar battery separates a home owner from grid-reliance, and the often high costs that come with it. In addition to levelling up one’s independence, installing a solar battery is also an excellent way to reduce carbon footprints by having clean, renewable energy on hand whenever it is needed.

Which Batteries do I need?

When it comes to solar batteries, there is no one-size-fits-all formula. As mentioned, the battery to use depends on array capacity, exposure, and how much you plan on using it.

In Ireland, some of the most popular and well-known solar batteries are GroWatt, Duracel, Soluna, Dyness, Huawei & Libbi. All models are compatible with WattCharger-supplied panel systems. Our team will work with you to ensure that you adopt a battery that fits the nature of your pre-existing solar panels.

How much do solar batteries cost?

One of the largest hurdles for many consumers in Ireland when it comes to buying a solar battery is the cost. Perhaps as you predicted, these objects are not often cheap.

The cost of an average 5 kWh battery will add ~€3,000 to the cost of a panel array. If the system is larger, then multiple batteries may be needed to fully outfit the PV array in question.

Although the up-front costs of acquiring a solar battery can be initially daunting, the installation of a solar battery is likely to save money in the long-term.  In addition to potentially shielding you from grid costs and giving you the option for export, installing a battery once will mean that it is cheaper to replace in the future.

This is because the solar battery is comprised of 3 parts; the battery itself, the wiring and external mounting, and the inverter. The inverter can take up about half the cost of the battery, as it is the crucial element for the export of energy from the battery to the home, or back to the grid.

Will a solar battery work on my existing solar PV system?

The best news of all is that even if you have a solar PV array without a battery, installing one is completely possible. At WattCharger, our team of experienced experts will take all of the factors of your array into account to ensure that you get the battery that suits your needs best.

For further information, or to get started on your solar battery journey, do not hesitate to reach out to our team at WattCharger by asking a question via the form below.