The solution for the constant use of non-programmable renewable energy

The growing diffusion of non-programmable renewable generation and the future phase-out of coal plants will cause significant problems in the coming years in terms of the need to compensate for the variability of electricity generation and to reduce the inertia of the Italian electricity system.

This has entailed and will entail the continuous reduction of the “rotating masses” (the alternators connected to the turbines of the thermoelectric plants) of the electrical system and the consequent decrease in the inertia of the system.

In an electrical system, any imbalance between generation and power requirement causes, in the first moments, a slowing or acceleration of the rotating masses which corresponds to a frequency variation.

It is absolutely important that this variation is minimal (in any case contained within a predetermined range) and has the shortest possible duration.

The variations will be larger (and dangerous for the equilibrium of the system) in inverse proportion to the inertia of the rotating masses.

The inertia of the system is therefore a critical factor for the frequency stability of the electricity grid and represents a safety factor against possible blackouts, even geographically extended.

By virtue of their technological characteristics, electrochemical storage is one of the possible enabling factors of the energy transition underway, contributing to:


Provide ancillary network services (e.g. frequency regulation) and support for system stability (e.g. inertia)

Limit wind and PV curtailment (expected to increase in the absence of other measures) and reduce grid congestion phenomena

Optimize investments in network infrastructures

From the point of view of grid services, batteries represent a particularly suitable technology for supplying the frequency regulation service (Fast Reserve, Primary and secondary) and voltage regulation.

Source Terna 2020 Development Plan