Abstract
The Transmission System Operators (TSOs) from Portugal and Spain do not procure Frequency Containment Reserve (FCR) through market mechanisms. A Virtual Power Plant (VPP) aggregating sources such as wind and solar power and hydrogen electrolysers (HEs) would benefit from participation in this ancillary service market. The methodology proposed in this paper allows to quantify the costs of the participation of the Iberian TSOs in the FCR Cooperation as well as the revenues of a VPP that aggregates wind and solar power and HEs. Results are produced using real data from past market sessions. The Portuguese TSO would have paid roughly 10 M€ to participate in this market in 2022. Using data for the same country and year, a VPP (aggregating the HEs expected to be connected by 2025) would have revenues over 2 M€. © 2023 IEEE.

Abstract
This paper investigates the contribution of hydrogen electrolysers (HEs) for frequency related Ancillary Services (AS), namely Frequency Containment Reserve (FCR), Synthetic Inertia (SI) , Fast Frequency Response (FFR) in future operation scenarios in the Iberian Peninsula (IP) considering low system iner-tia. The proposed framework for analysis consists of a dynamic model developed in MATLAB/Simulink. Simulations show that an instantaneous inverter based resource (IBR) trip induced by a grid fault may lead to the occurrence of values of Rate of Change of Frequency (RoCoF) close to undesirable thresholds if the FCR is provided solely by the conventional generators. The obtained results illustrate that HEs can outperform conventional generators on the provision of FCR. Furthermore, the FCR is unable to unlock the full potential of fast responding HEs. This suggests the advantage of providing additional AS such as SI or FFR in critical periods. Simulations also show that the benefit of additional AS can be limited in specific conditions, especially depending on the evolution of HEs' ramping capabilities, but are still a relevant complement to other solutions designed to deal with low inertia in power systems such as synchronous compensators.& COPY; 2023 Elsevier Ltd. All rights reserved.