What does the requirement of solar panels for large electricity consumers mean?
As of June 30, 2025, the Flemish government requires that buildings with high electricity consumption install a minimum amount of solar panels. Given the exemplary role that the public sector represents, the purchase threshold for these buildings is set four times more stringent. The reference year for this consumption will be taken in 2021 or later if the threshold was not exceeded then.
Indeed, Flanders wants to accelerate the reduction of dependence on Russian gas and accelerate the rollout of renewable energy. To this end, as part of this endeavor, Flanders requires that a minimum portion of their horizontal roof area (=measurable area on a ground plan or aerial photo) be covered with solar panels.
Who is this obligation of solar panels for?
As of June 30, 2025, large electricity consumers that draw more than 1,000 megawatt-hours annually from the power grid will in principle have to produce some of that power on their own roofs using solar panels. The installation must also be commissioned by this date.
For all public buildings, the off-take threshold is set more strictly at 250 megawatt hours. The definition of public buildings includes buildings owned by the federal, Flemish , provincial and municipal governments, but also includes public enterprises, educational institutions, welfare facilities and health facilities.
What does the obligation entail?
If the off-take threshold was exceeded in 2021, the rule applies that there must be a minimum of 12.5 Wp per m² horizontal roof area by June 30. This is the roof area visible from a ground plan/ aerial photograph and therefore does not take into account unsuitable roof areas for solar panels. If the threshold is exceeded later than 2021, the requirement takes effect by Jan. 1 of the fourth calendar year after.
The obligation is also becoming systematically stricter: from 2030 it will be 18.75 Wp/m² and in 2035 25 Wp/m². In addition, the threshold value for public buildings from 2026 will also be 100 MWh instead of 250 MWh.
The solar panels do not have to be placed on the roof, but can also be placed, for example, on grounds, carports, bicycle sheds or on the water. There are also exceptional measures such as the installation of a wind turbine, bio CHP or a participation in renewable energy. Furthermore, there are also certain deferral rules if a roof needs to be renovated, a building needs to be demolished or a new building is added.
How do I apply this integration of solar panels?
Ingenium Group can support you in the entire process. You can contact us for the preparation of patrimony scans, energy studies and the design of PV installations.
Would you like to learn more about our services related to solar panel integration or would you like to get a head start on rolling out renewable energy at your site? Then contact Hannes Stubbe at hannes.stubbe@ingenium.be or call 050 40 45 30 for a no-obligation consultation and discuss the possibilities.
