Solar panels for collective self-consumption

A collective self-consumption installation is the sum of n individual installations that share a series of common infrastructures: a single project, a single wiring, a single inverter, a single legalisation and processing.

For this reason, all participants must sign a sharing agreement that establishes the % of the installation held by each participant.

From here, it must be understood that sharing energy is a virtual phenomenon in which we don't actually know where the electrons go physically.

For this reason, in a collective self-consumption installation it will be necessary to install a generation meter that will read and inform the distribution company of the total energy generated.

The distribution company will apply the sharing coefficients from the agreement and allocate to each participant the corresponding share of generation. From here it will compare the generation with the consumption read by each participant's consumption meters and carry out the corresponding balance, ultimately billing each one the difference between their consumption and their generation. If this difference is less than 0, the corresponding surplus will be applied.

Currently, the maximum straight-line distance in the orthogonal plane between the generation meter and the consumption meter is 5 km. This limit was extended by Royal Decree-Law 7/2026, which updated the previous 2 km cap established by RD 244/2019.

Energy can be shared both in low voltage (LV) and in medium voltage (MV).

In addition to the distance criterion, sharing is also enabled if participants are connected to the same low-voltage line from the same transformation centre, or if the first 14 digits of the cadastral reference match (shared buildings or plots).

Sharing only the surplus of an individual installation is not an option contemplated by the regulations. When an installation is individual, the surplus energy is automatically fed into the grid and cannot be selectively redirected to neighbours.

That said, there are two legal routes for your installation to also benefit your neighbours:

• Transforming it into a collective self-consumption installation: in this case you will share all the energy generated (both self-consumed and surplus), not just the surplus. The sharing percentages are agreed in advance between the participants through a sharing agreement.
• Opting for the simplified surplus compensation scheme: the surplus is fed into the grid and your electricity retailer discounts its value on your bill. You don't physically share the energy with specific neighbours, but you contribute to the system and maximise the return on your installation.

Communal rooftops are not the private property of the top-floor neighbour; they belong to the community of residents. The regulations to follow depend on the territory:

In Catalonia (Catalan Civil Code):

• Both for individual and community-use installations on the common roof, it is necessary to request permission from the community.
• The owner must call a meeting, include the request on the agenda, and obtain approval by simple majority of those present.

In the Balearic Islands (Spanish Horizontal Property Law):

• Individual self-consumption in a private area (private terrace, private courtyard): no permission or notification required.
• Individual self-consumption on the communal roof: a prior notification to the community president is sufficient (art. 17.5 LPH). No meeting needs to be called.
• Collective self-consumption: requires approval by one third of the owners representing one third of the participation quotas (art. 17.2 LPH).

In both cases, the thresholds are designed to facilitate the energy transition and prevent individual or collective initiatives from being blocked. You can see real examples in our collective self-consumption projects. If you need help preparing the proposal to present at the meeting or the notification template, contact our team: we will support you throughout the process.