Home batteries on solar panels: an interesting investment?

Find out more about the home battery premium on the Flemish government website (Dutch only)

Applying for a home battery premium: good to know

• You will need to submit a full premium application within 9 months from the date of commissioning (= the AREI safety inspection and approval) the installation.
• The commissioning date (AREI approval) defines how much premium you receive and the conditions attached to it.  

NB: if you submit a premium application after 1st January 2022, showing a commissioning date (AREI approval) in 2021, you will come under the premium conditions for 2022.

A few examples:

• Example 1: commissioning date (AREI approval) in February 2022 and full premium application submitted in April 2022: premium rate for 2022.
• Example 2: commissioning date (AREI approval) in December 2022 and full premium application submitted in February 2023:  premium rate for 2022.
• Example 3: commissioning date (AREI approval) in February 2022 and full premium application submitted in December 2022: you are NOT eligible for the home battery premium, because your premium application was not submitted within 9 months of the AREI approval date.

In view of the processing time required at Fluvius to produce the paperwork, the affidavit by the installer has been modified since 1st November 2021.

In the affidavit, the installer declares that  

• a local production unit is in place at the access point and is correctly registered with Fluvius,
• a digital meter has been fitted, and
• the home battery is correctly registered with Fluvius.  

The Flemish Energy and Climate Agency (VEKA) will check these points when dealing with your application for a premium. A certificate from Fluvius is no longer requested with the premium application. Use the new affidavit for this.

You (or your installer) must register the installation via the Fluvius website.

But you do not have to wait for your application to be processed at Fluvius to apply for the home battery premium. By way of supporting document, all that is required is an affidavit from the installer for premiums applied for from 9th November 2021.

If your application is still being processed by Fluvius, you should ask your installer to provide an updated affidavit (from 1st November 2021).

We have already said that business is booming for home batteries. The same thing applies to premium applications, so allow a processing time of 4 to 6 months for premium applications from December 2021.  

If you want to look at the profitability of a home battery, there are a number of factors that have a considerable impact:

• How much energy in total do you use as a family?
• How much of your solar energy do you use yourself?
• The capacity of the home battery
• The government premium that you receive
• Your current energy contract  

For most of these factors, making an improvement is the main message!

If you already have a digital meter, check your usage data on mijn.fluvius.be.

Select the right home battery, based on your consumption (i.e. don’t choose one that’s too big/expensive).

To ensure that the cost of your home battery sufficiently justifies the benefits, installing a battery of 1 to 1.5 kWh per kWp (kilowatt peak) from the solar panels is recommended. After the introduction of the capacity tariff, this will shift to 1 kWh per kWp from the solar panels.

For an average solar panel installation of 4 kWp, ideally you should install a home battery of 4 to 6 kWh.

Maximise your self-consumption of solar power, apply for your premium in plenty of time… and also take a close look at your energy contract.  

Solar panels, a home battery and ‘injecting’ the solar power that you don’t use into the grid go hand in hand. There are a number of changes happening in this regard in the different regions of Belgium. Take a look at them here.

In Flanders

Prosumer tariff or injection tariff

By the end of 2024, approximately 80% of the new digital meters will have been installed and by July 2029, everyone in Flanders should have one.

If you live in Flanders and have solar panels, but don’t yet have a digital meter, then you pay a fixed prosumer tariff each year. This means you are both a producer (i.e. you inject your surplus power into the grid) and a consumer (when the sun doesn’t shine, you draw down power from the grid). If you coordinate this production/consumption nicely, the final reading on your meter will be approximately zero.

This means it will be as though you haven’t used anything from the grid. But in actual fact, you are a double-user of the electricity grid. Which is why the Flemish government introduced the prosumer tariff, which is charged on the assumed take-up by the grid, depending on the capacity of your solar installation and the region where you live.

TIP: if you opt for a home battery, then the smart thing to do would be to request a digital meter as soon as possible from Fluvius.

With a digital meter you can measure precisely how much power you are drawing from the grid and how much you are injecting back into it again. The prosumer tariff then lapses.

The energy that you take from the grid and the (unused solar) energy that you inject into the network are calculated separately.

1. You pay the energy charges, distribution network tariff and taxes on your total (gross) drawdown from the grid, summarised as the ‘net charges for gross drawdown’.
2. For the quantity of electricity that you inject into the grid, your energy provider pays you an amount set out in a power feed-in contract.  

Using the VREG V-test you can check to see which power feed-in contract gives you the best feed-in payment.  

You will find a clear summary of Frequently Asked Questions and answers about the prosumer tariff (Dutch only)  at VREG.

Capacity tariff

In Flanders the method for calculating the tariff for the grid charges on electricity bills is changing.

When will this change take place? The roll-out of the so called ‘capacity tariff’ by VREG was initially planned by 1st January 2022, then by 1st July 2022. Now, (at the request of Fluvius and Febeq, the federation of energy companies), it has again been postponed to 1st January 2023.

What is changing exactly? It is another way of spreading the grid costs on all consumers. The new capacity tariff calculates the costs for the consumption from the electricity grid not any more completely based on the quantity of electricity you use, but largely on the basis of the the usage peaks.

In other words, the capacity tariff takes into account the usage peaks of your family or home.

The distinction between the day and night tariff will also disappear. The grid tariff you pay will therefore no longer depend on the moment of consumption.

The home battery will then help you to use as much energy as possible from your solar panels. This means you will take less power from the grid, so that the risk of ‘peaks’ in your consumption from the grid is reduced. It also means you will make an additional saving on your energy bill.

So, a home battery will be more attractive than it was before, particularly in Flanders!

Prosumer tariff

In Wallonia

In the past and for a long time, the owners of solar panels did not have to pay anything extra to inject their surplus power into the grid. But that has now changed. From 1st October 2020, the Walloon government also introduced the prosumer tariff.

In 2022 and 2023, the Walloon Region will continue to partially compensate the prosumer tariff, albeit at a rate of 54.27%. This will still be done through a premium paid by the grid operator. So the remaining 45.73% will be paid for by the prosumers.

Prosumer tariff in Wallonia

In Brussels

As was the case in Wallonia, the Brussels Region did not have a prosumer tariff for a long time. This changed in 2020 as well, with a lower payment for the power that you inject.

The new system with an injection tariff has applied in Brussels since 1st November 2021. The bidirectional digital meter will measure the amount of electricity you purchase and the amount you consume separately. You pay for the electricity that you draw down from the grid at the drawdown tariff. You then receive a predefined amount per kWh for the electricity you inject: the injection tariff. This amount depends on your energy provider.

Injection tariff in Brussels (Dutch only) 

Read here (Dutch only) to find out how the investment premiums are paid in the regions outside Flanders.

After all this information, the key question still remains: is purchasing a home battery still a good idea?

A home battery is and remains a hefty investment that will not pay for itself for years.

That is a fact. But on the other hand, it doesn’t look as though the current high energy prices are going to come down any time soon. But if you have solar panels and want to get more energy out of them, then installing a home battery is certainly worth considering.

In the meantime, you can apply these tips:

1. To achieve maximum performance from your solar panels, you should first try and increase the amount you consume from the panels yourself. For example by using the washing machine, dishwasher and tumble dryer as much as possible at times when your solar panels are generating power – i.e. during the day when the sun is shining.
2. Do you have an electric (heat pump) boiler or electric vehicle? If so, gear their use to the production from your solar panels. In many cases, it pays to automate the process via an energy management system (EMS).
3. After that, if you own a digital meter (based on your consumption data) and using the Flemish simulator, you may want to consider whether investing in a home battery is worth it.