The energy transition involves a widespread diffusion of generation from renewable energy sources and a simultaneous reduction in thermoelectric generation which has so far constituted a fundamental resource for the frequency regulation and inertia of the electricity system. Assessments regarding new flexibility resources, on the one hand, and the evolution of inertia, on the other, are therefore necessary.
The first activity concerns upward transient (so-called “inertial”) frequency regulation of wind power and ultra-rapid regulation of electrochemical Storage Systems (SSs), as defined by Terna specifications. The simulations of disturbances on future scenarios of the Sardinian system have shown that the transient wind regulation initially improves the frequency trend, but, in certain initial conditions of the wind generators (linear section of the wind-power characteristic), it can cause a subsequent disturbance due to the restoring effect of the rotor speed. The ultra-rapid regulation of the SSs, on the other hand, is always beneficial for the system and mitigates any disturbance caused by wind farms.
The second activity describes the evolution of inertia and evaluates the time profile of an inertia intensity index per unit of power generated on a 2030 scenario. The activity is preliminary to future studies of the influence of the spatial distribution of inertia on frequency stability.