Robust power systems can generally accommodate large-scale renewable generation with limited stability impact; however, weak grids, such as those in rural areas or remote islands, remain vulnerable to severe transient disturbances. This paper presents a dynamic stability assessment of a remote island power system integrating an electrolyser facility with a wind power plant (WPP). Although steady-state operation is satisfactory, WPP tripping events cause severe disturbances that jeopardise secure grid operation despite the electrolyser's rapid ramp-down response. Synchronous condenser (SynCon) and battery energy storage system (BESS) technologies are evaluated individually and in hybrid configuration under partial and complete generation-loss scenarios. Baseline results confirm that acceptable steady-state performance does not ensure transient security. Immediately after the event, the electrolyser remains at its pre-event demand, requiring the grid to replace the lost generation instantaneously. The SynCon improves the initial transient response but requires substantial flywheel capacity to prevent frequency collapse. The BESS provides controllable active-power support but requires a considerable power rating when used alone. The hybrid SynCon-BESS configuration demonstrates complementary operation, where SynCon arrests the initial frequency decline, while BESS bridges the remaining load-reduction interval. Results demonstrate a practical approach supporting the stable integration of renewable generation and electrolysers in weak grids.