Deadline approaching for large electricity offtakers to install solar panels

Legal Eubdate
2 July 2024

To further shape tomorrow’s sustainable energy network, the Flemish government is requiring large electricity offtakers to install (additional) solar photovoltaic (PV) panels. Large electricity offtakers still have until 30 June 2025 to do so. This deadline refers to the actual commissioning of the installation; merely placing an order before the deadline is not sufficient. Since that deadline is now less than a year away, and order books are already well filled, doing nothing is not an option. We briefly summarise the main points of interest which will help you plan and take timely action if necessary.

Who is affected?

The solar PV obligation applies to persons (individuals, companies or public authorities) that consumed more than 1 GWh of electricity per offtake point per year in 2021. For public authorities, the threshold is much lower: 250 MWh per year in 2021, and from 2026 as low as 100 MWh per year. Individuals or public authorities that did not exceed this threshold in 2021, but did exceed it in a subsequent year “X”, are allowed until 1 January of year “X+4” to meet the solar PV obligation. Thus, a new deadline – 1 January 2026 – will already arise for individuals and public authorities that first exceeded the threshold in 2022.

Incidentally, this obligation applies not only to owners of buildings, but also to individuals and public authorities who have a long lease or superficial rights on (parts of) buildings.

How many solar panels should you install, and where can you install them?

The question then arises as to what obligations rest on those who exceed the offtake thresholds. Here, the starting point is that these large customers must install enough solar panels before the deadline in order to attain a minimum peak power capacity. That required capacity depends on the roof area of buildings connected to the offtake point and will be increased every five years. By 30 June 2025, large customers must have installed 12.5 Watts peak per square metre of roof area (“Wp/m²”). From 1 January 2030, that will increase to 18.75 Wp/m², and from 1 January 2035 to as much as 25 Wp/m². This will allow large electricity offtakers to sufficiently spread the necessary investments.

However, there are two limitations in connection with the required installed power capacity. First, the customer is not required to install more power capacity than a percentage of what it consumes itself the first time it exceeds the threshold of 1 GWh, 250 MWh or 100 MWh. In addition, a comprehensive grid study can also provide sufficient proof that the maximum connectable injection capacity of the grid has been reached.

In order to attain the required capacity, the large electricity offtaker then installs its solar panels in one of the following locations:

  1. on the roof or facade of buildings connected to the offtake point covered by the obligation;
  2. on the roof or facade of other buildings, on marginal land (such as verges), carports, bicycle sheds, water surfaces, or by way of an umbrella installation in agricultural areas located on the same site or connected by a direct line to the offtake point; or
  3. on buildings, marginal land, carports, bicycle sheds, water surfaces or as an umbrella installation in agricultural areas located on another site in Flanders belonging to the same large offtaker. In this case, the panels will only count if they were commissioned after 1 January 2023.

Can you also opt for other forms of renewable energy?

Besides installing solar panels, large electricity offtakers can also meet their solar PV obligation by alternative means. For example, large electricity offtakers can also achieve the required capacity utilising wind turbines or biomass or biogas (excluding biomethane) cogeneration (CHP) units. Under strict conditions, the solar PV obligation can also be met by participating in other renewable energy projects in Flanders.


The deadline for mandatory installation of solar panels on buildings with high electricity consumption is fast approaching. In order to comply with this obligation, both companies and public authorities should prepare properly and in good time, also factoring in the need for a certain lead time before a solar PV project can become operational.

We are ready to support you in this regard. If you have any questions about the solar PV obligation or other energy law issues, you are welcome to contact our team for expert legal advice.