The home battery on solar panels: an interesting investment?
Since Tesla introduced the home battery in 2015, things have been going well for this device for home storage of energy, mostly solar energy. After Tesla, many other brands also launched their own version of the home battery on the market.
Is investing in a home battery to store self-generated solar energy still an interesting investment? Find out here.
Home batteries on the rise
The recent figures are very telling: the home battery market is still booming. In 2024 alone, a whopping 73,258 home batteries were registered with Fluvius.
This strong growth was aided by government subsidies, which have ended (since the end of 2024), but also by the elimination of the reverse metering system for existing solar panel installations in Flanders.
The digital meter and the home battery
Fluvius is installing digital meters everywhere. By the beginning of 2025, about 66% of the digital meters had been installed, but by July 2029, every Fleming must have one.
With the digital meter, you only pay for the exact amount of electricity that you draw from the grid. For the electricity that you inject into the grid, you receive compensation.
How much does a home battery cost?
The cost of a home battery depends on a range of factors, such as the brand and the capacity. The higher the capacity, both in terms of charging capacity and the speed at which the electricity can be delivered, the higher the price tag.
The cost for a home battery of 3 kWh is estimated to be about 4,000 euros, and for a home battery of 8 kWh, the prices range between 5,000 and 8,000 euros.
This hefty amount usually does not allow for the home battery to be recouped as quickly as your solar panels (average 8 years).
What is the payback period of a home battery?
How long does it take for a home battery to pay for itself? There are quite a few myths circulating about the payback period. In reality, the payback period for a home battery is between 8 to 14 years, up to 20 years.
- Calculate the payback period for yourself
- A handy overview of the most frequently asked questions can be found at https://energiesparen.be/thuisbatterij
How profitable is a home battery?
When you want to look at the profitability of a home battery, there are several factors that can have a significant impact:
- How much energy your family uses in total
- How much of your solar energy you consume yourself
- The capacity of the home battery
- Your current energy contract
For most of these factors, optimization is key!
If you already have a digital meter, check your usage data at mijn.fluvius.be
How do you choose the right home battery?
Choose your home battery based on your consumption (so, also don't choose one that's too large and expensive).
In 2023, the capacity tariff was introduced, which means your network rates are not only dependent on the amount of electricity you consume, but also on how much you burden the electrical grid. To ensure the benefits of your home battery outweigh the costs, it is advised to provide a battery of 1 kWh for every kWp (kilowatt peak) of solar panels.
For an average solar panel installation of 4 kWp, you ideally place a home battery of 4 to 6 kWh.
Tip to maximise the output from your solar panels and home battery: use as much of your own solar energy as possible and also examine your energy contract.
Injecting excess energy into the grid: how does that work?
Solar panels, a home battery, and injecting the solar energy you don't consume into the grid, go hand in hand. In this respect, there are various developments ongoing in the different regions of our country. Take a look at them here.
In Flanders
Reversing meter: prosumer tariff or injection tariff
As an owner of solar panels, you are a prosumer. This means you use the electricity grid, but also inject power into the grid. Those who do not yet have a digital meter, but do have a reversing meter, pay an annual fixed prosumer tariff.
The way this tariff is charged has changed since July 1, 2022. The prosumer tariff is spread throughout the year, according to the normal number of hours of sunshine per month. The prosumer tariff will remain in effect as long as you have a reversing meter. It will permanently disappear once you switch to a digital meter and will then be replaced by the injection tariff.
Digital meter: net metering contract
If you opt for a home battery, it's smart to request a digital meter from Fluvius as soon as possible.
With a digital meter, you precisely measure how much electricity you draw from and inject into the grid. The prosumer tariff then no longer applies.
The energy you draw from the grid and the (unused solar) energy that you inject into the grid are separately accounted for.
- You pay: energy costs, distribution network tariff, and taxes on your total (gross) withdrawal from the grid, summarized as 'net costs for gross withdrawal'.
- You receive: a compensation from your energy supplier for the amount of electricity that you inject into the grid, set in a net metering contract.
Via the V-test by VREG you can find out which net metering contract offers the best compensation for return.
Capacity tariff
In 2023, the capacity tariff was introduced. This is a different way to distribute the net costs among all users. The new capacity tariff calculates the costs for using the electricity grid not entirely based on the amount of electricity you draw, but largely based on peak usage.
Thus, the capacity tariff considers your household or building's consumption peaks.
Moreover, the distinction between daytime and nighttime tariffs has disappeared. The network tariffs you pay no longer depend on when you consume.
The home battery will then help to utilize as much energy from your solar panels as possible. This results in lower electricity withdrawal from the grid, hence reducing the risk of 'peaks' in your grid consumption. This translates into further savings.
A home battery, therefore, becomes more advantageous, especially in Flanders, than it was before.
In Wallonia
Prosumer Tariff
In 2020, the prosumer tariff was also introduced in Wallonia. During the first two years, owners of solar panels received an invoice for the prosumer tariff, but they also received an annual premium from their network operator. As a result, the cost of the tariff was compensated 100%.
In 2022 and 2023, the Walloon Region continued to partially compensate for the prosumer tariff, at 54.27%. This was still done through a premium paid by the network operator. The remaining 45.73% was therefore at the expense of the prosumers. (source: engie.be)
Starting from 2024, prosumers will pay the full prosumer tariff without compensation.
If the prosumer has an electromechanical meter, the prosumer tariff is a fixed rate, based on the power of the solar panels (EUR/kVA). If, on the other hand, they have a digital meter, the tariff is proportional. This means that it takes into account the electricity consumed (EUR/kWh drawn from the grid). In the latter case, the prosumer tariff is at most the amount of the fixed prosumer tariff that normally applies to that solar panel system.
For new installations certified after January 1, 2024, the injection tariff system will apply. In this system, consumption and injection are measured separately, and prosumers no longer pay a prosumer tariff.
In Brussels
Injection Tariff
Just like in Wallonia, a prosument tariff was introduced in the Brussels-Capital Region in 2020: a lower compensation for the electricity that you inject.
Since November 1, 2021, the injection tariff system has been in effect in Brussels. This system replaces the previous compensation mechanism and applies to installations with a bidirectional meter, which separately records both the consumption and injection of electricity. The bidirectional digital meter measures the amount of electricity you consume and that you inject separately. You pay for the electricity you consume from the grid at the consumption tariff. You receive a predetermined amount per kWh of injected electricity: the injection tariff. This compensation depends on the energy supplier.
Answer to all your energy questions
On the website of the CREG, the Commission for Electricity and Gas Regulation, you can find the path to reliable answers to all your questions about the regulation and reconciliation of energy.
You will also find the 3 regulators in our country:
They are responsible for the organization and operation of the regional electricity and natural gas markets, advise the regional governments, and monitor the application of decrees and decisions, approve the distribution network tariffs, and organize a mediation service where consumers can go if they have problems with their supplier or distribution network operator.
Of course, you can also contact your energy supplier with specific questions about your situation in your region.
Is a home battery a good investment?
After all that information, the key question remains: is purchasing a home battery still worthwhile?
Solar panels reduce your energy bill. And with a home battery, you use more of your own produced energy from solar panels. In times of significantly increased energy prices, this is certainly advantageous.
A home battery remains a substantial investment that only pays off after several years. That's a fact. However, on the other hand, it does not seem likely that the high energy prices will drop again soon. If you want to maximize the output from your solar panels, then a home battery is definitely worth considering.
Still unsure? In the meantime, you can already apply these tips:
- First try to increase your self-consumption. For example, by using the washing machine, dishwasher, and tumble dryer as much as possible at moments when your solar panels are generating electricity, during the day when the sun is shining.
- Do you have an electric (heat pump) boiler or an electric vehicle? Then synchronize them with your solar panels. In many cases, it pays to automate this process through an energy management system (EMS).
Finally: one more important tip!
When purchasing a home battery, check whether the extended producer responsibility (the take-back and recycling of the discarded battery) is arranged!
Like all other batteries, the home battery is also subject to the take-back obligation or acceptance obligation by the producer/importer. This is regulated at the European level. The producer/importer must provide the opportunity through the installer to take back the home battery at the end of its life.
The producer/importer is the company that markets the batteries in the Belgian market and thus has the acceptance obligation in Belgium.
A producer/importer that is affiliated with Bebat pays an environmental contribution on home batteries. This contribution can be passed on to the end customer.
Definitely worth discussing this as well during your purchase!
