Luxembourg’s smart meter branded as Smarty by the electric grid managing company CREOS allows monitoring your electricity consumption and production as well as your gas consumption. Additionally it allows the grid operator to control certain electrical appliances in your household.
Shedding relays – relais de délestage
If parts of the electricity grid in Luxembourg are becoming overloaded or unstable, the grid operator can remotely command the Smarty smart meter to take action to protect the grid. Smarty can diminish the power of domestic car charging points from 11kW to 7kW. As of writing this, CREOS confirms not using this feature (January 2025).
Smarty can also reduce the power of photovoltaic systems to about a third of the available power, if your PV management system allows this. If not, the shedding relay (FR: relais de délestage) will fully shut down the PV system when asked by the grid operator. It seems that this is currently not used neither by CREOS.
Smarty can also limit charging power of night storage heaters (DE: Nachspeicherheizung, FR: chauffage à accumulation) systems through shedding relays.
Billing
Every 15 minutes, the Smarty transmits to the grid operator (or the third party data collection partner) the average electricity consumption of the last 15 minutes. This is used to bill the quantity of electrical energy that was consumed, as well as the monitoring of the load that you used on the grid.
As of 1st January 2025, every household in Luxembourg is categorised in a power consumption category. Most households are in category 3 kW. Households with electric cars or heat pumps might be categorised into 7 kW or 12 kW categories. The monthly costs depend on the power consumption class that you are in.
If you are in the 3 kW category, and you drag 5 kW from the grid for about an hour, you have to pay additional fees (FR: supplément pour le dépassement), in this case: 5-3=2 kWh, which currently equals to 2*0.1139€ = 0,2278€.
If you use for example a (tea) water heating device that pushes your maximal power consumption over the 3 kW limit for about a minute, the fact that Smarty calculates the average over 15 minutes should assure that this short stepping over your category’s boundaries should not be visible on your invoice.

To find out what your power category is, check your electricity provider’s portal, like myenovos.eu.
Balancing out consumption and production on 3-phase grids
When you are running a balcony power plant (DE: Balkonkraftwerk), you might be interested in how the Smarty manages billing or settlements of electricity production over the three phases. In Luxembourg, a normal household is connected to the power grid on 3 phases each capable of pumping 40A of current.
When you connect such a small photovoltaic system to a power socket on your balcony, it will feed the produced electricity only to the phase where you connected it. But this might not be the phase where your house is consuming most electricity, so you are feeding your produced electricity to the grid and drag the electricity from the grid that you need on the other phase (buying from thew grid is much more expensive then what you get paid for injecting electricity).
But there is good news: the smarty will balance this out (DE: saldierender Stromzähler), as it sums up power consumption on all three phases and power production on all three phases and only considers the difference for billing. Without this, a (mono-phase) balcony power plant is not really interesting for private use.
[Unfortunately I only have oral confirmation of this from by an engineer. No guarantee on this information. It might also change over time.]
Monitoring your consumption and production
You have three possibilities to extract consumption and production data from your Smarty smart meter.
(1) By default, Smarty shows the most important values in a 5 seconds rhythm. Additionally: With the green button on your Smarty, you can cycle through the data that the meter gathers. To understand what value is currently displayed, Smarty adds the OBIS code to the display.

(2) Plug the Smarty+ dongle into your Smarty meter’s P1 port and monitor your data on your smartphone
(3) Connect the P1 port over a serial / USB to a computer and monitor your data using a home automation software like for example openHAB with the help of the DSMR binding.
When using the P1 port, solution 2 & 3, you need to ask the grid operator to give you the P1 decryption key.
Source for most of the information above: https://www.creos-net.lu/en/individuals/practical-info/faq
Some information was confirmed in a telephone discussion with a grid engineer in January 2025. The general disclaimer applies here too, of course!