Why solar systems above 4 kW in Portugal need a production meter and SIM card
If you are installing a solar system in Portugal, one detail that often comes as a surprise is the requirement for a production meter and SIM card on larger systems.
For solar installations with an installed capacity of more than 4 kW, Portuguese regulations require an additional production meter to be installed. This meter records the total electricity generated by your solar system, not just the energy you export to the grid.
Why is a production meter required?
The production meter allows E-REDES, Portugal’s grid operator, to remotely monitor how much electricity your system is producing.
This is important for two main reasons:
1. Grid management
E-REDES needs visibility of production data to help manage grid stability and understand how much solar energy is being injected into the network.
2. Surplus energy validation
If you export surplus electricity to the grid and are compensated for it, the production meter provides the official data used to validate how much energy your system has produced.
Why is a SIM card needed?
The production meter includes a GSM modem, and that modem requires a SIM card so it can communicate with E-REDES remotely.
Without the SIM card, the meter cannot send production data as required.
What type of SIM card is needed?
This is not usually a standard prepaid mobile SIM. The SIM card must typically meet specific technical requirements, including:
- M2M (Machine-to-Machine) type
- PIN code disabled
- At least 250 MB of data
- Support for CSD (Circuit Switched Data) and OTA (Over-the-Air) commands
Your mobile operator, such as MEO, Vodafone, or NOS, should be able to advise on a suitable option.
Who is responsible for the SIM card?
Unlike your home’s normal electricity meter, which belongs to E-REDES, the production meter, modem, and SIM card are the responsibility of the solar system owner.
That means the owner is responsible for:
- obtaining the SIM card
- paying for the data plan
- keeping the SIM active over time
In most cases, the simplest solution is to add the SIM to your existing monthly mobile contract, rather than using a separate prepaid SIM. This is often easier to manage and reduces the risk of the connection being interrupted.
Why it is best to arrange this before installation
Ideally, the SIM card should be ready before installation day so the installation team can fit it into the meter, configure it, and test everything properly.
If the SIM is not available in time, it can still be installed afterwards, but this usually means the homeowner will need to follow additional setup instructions later. For that reason, it is much better to have it ready in advance.
Final thoughts
This requirement can feel like a small technical detail, but it is an important part of making sure a larger solar installation in Portugal is properly connected and compliant.
At Sol Viva, we help homeowners understand each step of the process clearly, so there are no surprises before installation day.
If you are planning a solar installation in Portugal and want expert guidance, visit www.solviva.biz.