Collective self-consumption in a condominium with solar

Collective self-consumption is the configuration in which several owners of the same building jointly consume the energy produced by a renewable system installed on the common parts, typically rooftop photovoltaics. Energy shared within the same hour among the participants is remunerated by the GSE with an incentive tariff, while the surplus fed into the grid is valued separately. Unlike an energy community, all the parties are in the same building, which simplifies setup: often an owners' meeting resolution signed by the owners joining the self-consumer group is enough.

How energy sharing works in practice

The system produces energy that first feeds the condominium utilities and those of the individual members. The mechanism does not require a dedicated electrical line to each apartment: sharing is virtual and passes through the public grid. The GSE measures, hour by hour, how much of the energy produced by the system was consumed by the group's members and grants the incentive on that share, called shared energy. This is the heart of the economic benefit: the more the owners' consumption coincides with the hours of solar production, the greater the incentive.

The meeting resolution and the majorities

Installing the system on the common parts is an innovation aimed at producing energy from renewable sources under Article 1120, second paragraph, of the Italian Civil Code. The reduced quorum therefore applies: a majority of those attending the meeting representing at least half the value of the building. The resolution must authorise the works, approve the cost and appoint a referent to handle relations with the operator.

Joining the self-consumption group is voluntary: those who do not take part do not bear the share of the cost for the separable works and do not receive the benefits. Those who join sign the minutes or an agreement governing the split. It is good practice for the meeting to fix from the outset the criteria by which the incentive will be distributed, to avoid later disputes.

The referent's role

Every collective self-consumption configuration needs a referent, that is, the party who manages relations with the GSE, submits the applications, receives the payments and redistributes them to the participants. In a condominium this role is usually entrusted to the manager, but it can also be taken on by a delegated owner or a third-party producer. The referent must keep separate accounts of the flows and account to members for the sum due to each.

How to split benefits and costs

The distribution of the incentive among members must be defined with a clear, shared criterion. The most common options are:

• Split based on each member's actual consumption in the sharing hours, the one closest to the real benefit.
• Split based on the subscribed participation shares, useful when members financed the system to different degrees.
• Mixed split, taking into account both consumption and the investment made.
• A share allocated to the common parts to reduce the condominium's energy costs.

The construction and maintenance costs of the system, on the other hand, follow the criteria resolved: if the works serve all members, the cost is split among them under the agreement, while a dissenting owner remains excluded if the works are separable. Accounting clarity is decisive, because the incentive comes in every year and must be redistributed continuously.

Mistakes to avoid

The first mistake is confusing collective self-consumption with selling energy: nothing is sold here, a production is shared and an incentive is collected. The second is under-sizing or over-sizing the system relative to the building's real consumption: a system too large produces energy that ends up in the grid without full incentive, one too small does not cover consumption during sunlight hours. The third is failing to fix the distribution criteria in writing, leaving room for arguments every time a payment arrives.

To govern the configuration without drowning in calculations, management software such as AmministraPro helps register members, track incentives separately and automatically apply the distribution criterion chosen by the meeting. The features are described on the /funzioni page and the plans with their costs on the /prezzi page.