Thematic Investment Tax Credit for Solar Panels and Battery Systems

What exactly is the thematic investment deduction?

The thematic investment deduction is administered by the Flemish Energy and Climate Agency (VEKA) and allows you to deduct 40% of an eligible energy investment from your taxable profit. Important to know: this is not a subsidy, but a tax deduction, similar to the standard investment deduction but with a much higher rate (40% instead of the standard base percentage).

Here’s a concrete example: suppose your company invests €100,000 in solar panels and a battery. In that case, you can deduct €40,000 from your taxable profit. With a corporate tax rate of 25%, that’s a real tax savings of €10,000, on top of what you’re already saving on your energy bill. These two benefits combined make the business case for an energy project much stronger.

Who is the thematic investment deduction intended for?

The measure is widely applicable. In practice, virtually all types of businesses are eligible:

• Small and large corporations: 40% deduction from taxable income. (*)
• Self-employed individuals and members of the liberal professions: 40% through personal income tax.
• Nonprofit organizations: 40%, provided they are subject to corporate income tax.

(*) For investments made in 2025 (tax year 2026), large companies were legally entitled to only 30%. The bill, which is currently being drafted, aims to retroactively raise that 30% to 40%, so that even the major players will still be eligible for the same percentage.

There are, however, two clear conditions. The installation must be carried out in the Flemish Region. The address of the installation is what counts here, not your registered office. And the investment must be at least €1,000 (excluding non-deductible VAT).

In addition, there are two calculation requirements. The payback period (PBP) must be at least 3 years after taxes. And for large companies, the internal rate of return (IRR) must also be below 13%. It sounds technical, but EnergyKing automatically calculates this for your project using the mandatory VEKA template.

Which investments are eligible?

Currently, two categories have been confirmed, and these are the two that are most relevant to most companies:

• Solar panels (category 9): the entire PV system.
• Battery storage (category 8): including connection to solar panels or the grid.

Please note: Do you have a combined project that includes both solar panels and a battery? If so, you must submit two separate applications, one for each category. However, you should use the same TVT/IRR template for the entire installation.

Apply for the Thematic Investment Deduction with VEKA

The application process is handled through VEKA’s web application. We take care of the heavy lifting; you complete the online application yourself.

1. We will submit the application. At EnergyKing, we prepare the required TVT/IRR template (Excel, official VEKA format) and the technical description or energy study for each category. Without these documents, your application will not be processed.
2. Log in to the VEKA web application. You can do this using eID or itsme at apps.energiesparen.be/thematische-aftrek-aanvragen. If you are not the company’s director (as listed in the KBO), you must first request access rights from the director. Allow about 30 minutes for this process.
3. Fill out the application and upload the documents. Your KBO information is already pre-filled. You’ll need to add the fiscal year, the installation location, your invoices, and the documents we’ve provided. Then submit the application. The submission date is what counts.
4. VEKA makes the decision and sends a digital certificate. You forward that certificate to your accountant, who will include it in your corporate or personal income tax return. The deduction is applied to the profit for the fiscal year in which you made the investment.

When should you apply for the investment tax credit?

The thematic deduction is administered through a cooperation agreement between the federal government and the regions, which has not yet been published in the Belgian Official Gazette. As a result, there is currently no absolute deadline. The draft text states that applications submitted within 6 months of the publication of the cooperation agreement will be considered timely (expected no earlier than the end of 2026). However, it is best to submit your application early. VEKA will only process applications after the cooperation agreement formally enters into force, and those who apply early will be processed first.

One more thing to keep in mind: the increased thematic investment deduction is a permanent measure with no expiration date. What is reviewed every 3 years, however, are the investment lists that determine which investments are eligible. The current energy list is valid, in principle, through 2027. At the next review, expected around 2027, the conditions or the eligible investments may change. Do you have an energy project in mind? Then it’s best to invest within this period, while the current list is still in effect.

What should you keep in mind regarding the thematic investment deduction?

The benefit is great, but it’s not a given. Here are a few honest caveats so you know what you’re getting into:

• You need taxable income. A deduction only works if there is income to deduct it from. If you incur a loss, the deduction won't do you any good that year.
• It's not a cash subsidy. You don't receive money in your account; instead, you pay less in taxes. So the benefit is reflected in your tax return, not in a deposit.
• The conditions must be met. A payback period of at least 3 years, and for large companies, an IRR below 13%. If your project does not meet these requirements, it is not eligible for the program.
• The timeline is strict. The submission date is what counts, and the program is currently only confirmed for 2025 and 2026.

This is an attractive option for most companies with healthy profits and a solid energy project. If you’re unsure whether this applies to your situation, have it calculated in advance.

What should you keep in mind about the thematic investment deduction?

The combination of a lower energy bill and a 40% tax credit makes the business case for solar panels or a battery particularly strong today. At EnergyKing, we take care of all the heavy preparatory work—from the mandatory TVT/IRR template to the technical justification—so all you have to do is submit the online application. Not sure if your project qualifies? Have it reviewed in advance, and you’ll immediately know what benefits you’re missing out on if you do nothing.