In Luxembourg, the term “green electricity” is not legally defined. On the other hand, renewable energy sources are clearly defined by law.
Physically speaking, the electricity you consume comes mainly from the production plants closest to you (in the electrical sense) (N.B. the Cattenom plant, although close to the border, is far from the Luxembourg network in electrical terms).
To represent the electrical system, an analogy can be made with a large lake of water. This lake may be fed by many sources and there may be many withdrawal points. The aim is to keep the lake’s water level stable, so that the same pressure is always available at the withdrawal points. In the electrical system, it is the frequency of the alternating current (50 Hz) that must be kept stable. When there is more being withdrawn than being fed in, the frequency decreases, while it increases in the opposite situation.
To return to the example of the lake, if you want to take water from it, you can draw up a contract with any source that feeds the lake, because for the water level in the lake, it doesn’t matter if the source is close to your withdrawal point or not, the level of water in the lake will remain constant, as long as the source supplies as much water as you take from it.
It’s a similar situation for electricity. You can therefore sign a contract with a producer using renewable sources to supply the electricity system with the amount of electricity you consume. Even if this producer is not close to you, the electricity system is kept in balance (within certain technical limits). So contractually you consume the renewable electricity that is fed into the system for you.
To certify that the electricity that is fed into the electricity system for you comes from renewable sources, a system of certificates (guarantees of origin) has been implemented. This system makes it possible to trace electricity from its origin to its destination.
If you buy renewable electricity from your supplier, they must therefore have acquired the respective guarantees of origin from the respective producers, transferred them to Luxembourg and cancelled them for your consumption.
This system of guarantees of origin is clearly regulated to avoid abuses (e.g. double counting). For Luxembourg, the ILR monitors the system and checks each year that the quantities of renewable electricity sold are covered by the respective renewable production. The supplier will send you a ‘label’ showing the sources of the electricity they have supplied. These labels are verified by the ILR. The mechanisms currently in place guarantee that, on an annual basis, the quantities of energy sold by your supplier are actually produced from renewable sources.
Answering the question of whether the green electricity you consume is really green depends on your expectations. Physically, it will only be 100% renewable once all electricity generation within the interconnected network is generated using renewable sources. Contractually, it is renewable, insofar as the quantity consumed by you is produced somewhere from renewable sources. Your renewable supply contract therefore helps to replace non-renewable production with renewable production, thereby make the electricity system greener.
However, a contract for the supply of electricity from renewable sources should not prevent you from producing renewable electricity yourself, for example with solar panels, if your situation allows for this. By consuming the renewable electricity you produce yourself, you can actively contribute to the energy transition.