The level of inertia on the system is a key contributor to electricity system stability. Inertia is an attribute of the system related to the energy stored in the rotating motors of synchronous generators. It prevents system frequency from falling too quickly after a frequency disturbance (e.g. a generator trip). This is due to inertia stored in these rotating motors provides resistance to system changes. It is effectively free frequency response the ESO can count on in the case of a sudden fall in frequency.
In this week’s ‘Chart of the week’, Joe discusses how changes in demand due to COVID-19 are impacting this.