Summary
The inertia of electrical systems refers to the energy stored in the rotating mass of machines like generators and large motors. This inertia helps stabilize the grid by resisting changes in rotating speed, which is crucial for grid resilience during disturbances. The kinetic energy stored in these rotating masses helps reduce temporary power imbalances, giving the system time to react and stabilize its frequency. Traditionally, renewable energy sources (RES) like wind and solar do not provide inertia because they are typically connected to the grid through power converters, which decouple the generation side from the grid side. However, with newer converter control strategies, renewable energy systems can now provide synthetic inertia. This is achieved through grid-forming control and energy storage solutions that mimic the inertial response of traditional rotating machines.
Read more Read lessAs RES gradually replace many conventional power plants with rotating machines, the overall inertia in the system is expected to decrease. The geographic distribution of inertia inside the synchronous area is also changing due to the disparity of RES development or intrinsic country characteristics, such as large hydro potential. Inertia-related issues are expected to impact frequency control. Inertia acting as a frequency damper before entry into action of the
Frequency Containment Reserve (FCR), low system inertia results in high Rates of Change of
Frequency (RoCoF) and significant frequency deviations, which can lead to system instability including system splits, load shedding or even blackouts. Currently, inertia is not paid, despite its crucial role in ensuring two functions: the frequency stability of the interconnected Continental Europe synchronous area and the stability of each separated zone in the event of a grid split. This is a significant concern for the European
Network of Transmission System Operators for Electricity (ENTSO-E), as maintaining adequate inertia is vital for the reliable operation of the electrical system.
Inertia is treated at the European level through different angles such as: Connections Network
Codes (Requirement for Generators [1], Demand Connection Code [2] and High Voltage Direct
Current [3]) for technical capabilities of grid users and System Operation Guidelines (SOGL) for the dynamic stability assessments by Transmission System Operators (TSOs). Being defined as a system need, the Electricity Regulation 943/2019 provides for a possible market role for its valuation and procurement (market-based inertia procurement; cross-border market issue). This paper will address that last topic with a proposal for an ex-post reconciliation mechanism for inertia. The proposal aims at encouraging the provision of sufficient system inertia at all times with fair contributions from all participants. Based on inertia contribution assessments in year N+1, it would introduce reconciliation payments from the relatively undercontributing TSOs’ controlling area to the over-contributing TSOs’ controlling area. Such a mechanism would also nudge investments towards more distributed inertia in the grid for resilience during system splits.
Further details of its development and implications are developed in the paper.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | A1_10141_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | France |
| Study committees | |
| File size | 480 KB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
HIS Julien - EDF; VINAS Thierry - EDF
Keywords
