Inertia Challenges of the Portuguese Power System - a Prospective Analysis

The targets outlined in Portugal’s Energy and Climate Plan 2030 aim for the large-scale integration of electricity generation from renewable sources while gradually phasing out fossil fuel-based production. However, the high penetration of non-synchronous generation systems and a simultaneous reduction in the contribution from conventional synchronous generation plants pose significant challenges to power systems' reliable and stable operation. One challenge is the lack of inertia, which can reduce performance in response to disturbances. Therefore, understanding the challenges of the energy transition process and considering preventive and corrective measures when necessary is crucial. This work has two main objectives. First, we assessed the evolution of inertia in the Portuguese power system over the past decade and identified trends. Second, aligned with the scenarios established by the entity responsible for power system planning, we conducted a prospective analysis for 2030, 2040, and 2050. We identified potential situations with low inertia and discussed a comprehensive review of solutions envisioned in the sector. While all generation technologies contribute significantly to the system’s inertia, this contribution may not be sufficient to maintain adequate stability when the largest generating unit is lost, necessitating additional strategies.