Storage battery for condominium solar power

A storage system, or battery, stores the energy produced by condominium solar during sunlight hours to make it available when needed, typically in the evening. In a condominium with a photovoltaic system on the common parts, the battery raises the share of energy self-consumed and reduces that fed into the grid at low value. The result is better use of the system and a further cut in common consumption, but the value must be assessed carefully, because storage has a cost and a limited service life.

Why install storage

Solar produces when there is sun, but condominium consumption often concentrates in the evening or at times different from the solar peak. Without storage, the excess energy produced is fed into the grid and valued at a lower price than the energy that would have to be bought later. The battery bridges this time mismatch: it stores the daytime surplus and returns it when the system does not produce, raising self-consumption. In collective self-consumption or energy community configurations, this translates into a larger share of shared and therefore incentivised energy.

How to assess the value

Storage is not always worthwhile: its usefulness depends on the consumption profile and on the battery's capacity relative to production. Before resolving, some elements must be considered:

• The hourly profile of common consumption, to understand how much energy is needed outside sunlight hours.
• The battery's capacity relative to the system's production, to avoid costly over-sizing.
• The battery's service life and the charge and discharge cycles guaranteed by the manufacturer.
• The installation and maintenance cost compared with the expected saving and payback times.
• Any incentives for storage systems paired with solar in force at the time of the works.

An energy audit or a feasibility study helps size the system correctly, avoiding spending on capacity that would not be used.

How it is resolved at the meeting

Installing storage paired with the common solar system is works on the renewable plant of the common parts. Like other measures aimed at containing energy consumption and producing energy from renewable sources, it falls within the scope of Article 1120, second paragraph, of the Italian Civil Code, with the reduced quorum of a majority of those attending representing at least half the value of the building. The resolution must approve the cost, identify where the battery is placed and appoint whoever handles the technical relations and any procedures.

The allocation of the cost

The cost of the storage system is split among owners according to the thousandths of ownership when the system serves the common parts, or according to the criteria agreed in the self-consumption configuration if the battery serves the self-consumer group. It is good practice for the meeting, together with the resolution, to define how the greater self-consumption benefits generated by storage are reflected in the calculations, to keep consistency between who bears the cost and who benefits.

Safety and placement

Batteries must be installed in suitable, ventilated rooms compliant with the technical and fire-safety requirements, avoiding cramped spaces or spaces unfit for heat dissipation. The choice of placement, which must respect the decorum and usability of the common parts, should be agreed at the meeting and entrusted to a qualified installer who issues the conformity documentation. Periodic maintenance and monitoring of the battery's state of health protect the investment over time.

To manage quotes, resolutions, splits and the monitoring of a storage system's self-consumption benefits, management software such as AmministraPro keeps technical documents, dedicated accounting and owner communications together. The features are described on the /funzioni page and the plans with their costs on the /prezzi page.