Executive Summary

The energy sector is living a deep transformation, driven by the need to contrast climate change via the decommissioning of carbon-based power plant and rise of Renewable Energy Sources and thus meet the decarbonization objectives set in the Paris Agreement.

Power System Inertia can be defined as the ability of a system to oppose against changes in frequency exploiting the kinetic energy offered by the available resources such as the rotating masses.
As a result of the ongoing transition towards carbon neutrality, Transmission System Operators are challenged to manage an increasing share of converter-based renewable energy sources (RES), which are typically inertia less.

A low-inertia system is more sensitive to power imbalances and is affected by greater frequency variations following a disturbance, compared with a high-inertia system, and less stable reacting to severe perturbations (i.e. trip of large power stations) more subject to oscillations.

Most of the interviewees report no issues related to low inertia in the current power systems.

Lacking inertia is instead recognized as challenge for future power systems operation essentially due to decommissiong of carbon-based power plant and the introduction of RES.
Almost all the interviewees are already studying and implementing at least one remedial action to counteract future inertia reduction (i.e. synchronous condensers with flywheel or fast reserve).