In Belgium, your electricity bill is determined not only by how much energy you use, but also by how much power you draw at the same time. Two important concepts here are access power (toegangsvermogen) and peak power (piekvermogen).
Access power
Access power is the maximum electrical power you are allowed to draw from the grid. This is set contractually by your grid operator (such as Fluvius) and depends on your connection. Within these contractually defined limits you can set your own access power via mijnfluvius.be. The higher this power, the heavier your connection, and the higher the fixed grid costs.
After an increase, you can only lower it again after 12 months. After a decrease, you can reduce it monthly until the moment it is increased again. The new access power always takes effect on the 1st of the month following the change.
Peak power
Peak power is the highest power you actually use at a given moment. Grid operators increasingly look at this peak consumption, because high peaks put extra strain on the electricity grid.
The highest peak power of the month is carried through for the entire month. This means that even if a company drew a high peak only once and used low power for the rest of the month, it will be billed on that high peak for the whole month.
Watch out
When you change your access power, you must always notify your installer in time. It has to be adjusted in the control of your battery. If this does not happen, it can lead to exceeding your access power, resulting in high penalties.
An EMS that continuously takes your access power into account and shaves your peak power prevents such overruns automatically. That keeps your bill under control without you having to watch it manually.