Pumped-storage hybridization in the context of insular power systems

Abstract

Islanded power systems (IPS) are characterized by weak grid conditions, low overall inertia, and generation assets with unit capacities large relative to the total system load. Historically, such systems have relied on diesel-based synchronous generation, which offers predictable inertia but limited flexibility.
The system stability was achieved with simplicist concepts and regulations: spinning reserve as “catch all” approach, maximum share of intermittent renewables, and adjusted load shedding plans.

The ongoing transition toward integrating renewable energy sources, particularly wind and solar, introduces a fundamental challenge: as asynchronous, inverter-based technologies replace synchronous machines, the available system inertia declines. This creates vulnerability to frequency deviations during disturbances, most critically the loss of a large generating unit.

The present paper investigates a hybrid frequency support strategy, using supercapacitors integrated into a pumped-storage project (PSP) for an island grid. Simulation studies demonstrate that this approach can provide rapid active power injection, stabilize frequency, and reduce the severity of load shedding events.

Hugo Mesnage, Arnaud Porret, Nicolas Sauviat

Presented at Hydro 2025