Navigating Grid Challenges: Voltage-Reactive Power Control in the Integration of Power-to-X Facilities

This paper reviews the technical requirements for inverter-based facilities in modern power systems, focusing on Photovoltaic Power Plants (PVPPs), Wind Power Plants (WPPs), and Energy Storage Facilities (ESFs), with an emphasis on voltage-reactive power (V-Q) control. Case studies from in-force grid codes in Denmark and the United Kingdom are analyzed due to their high share of renewable energy and potential for Power-to-X (PtX) projects. Our findings suggest that existing requirements may apply to electrolysers, key components in PtX facilities, provided that their capability curves are properly defined, considering their electrochemical behavior, the absence of DC-side energy generation, and inverter operation. The paper highlights the need for harmonizing grid codes, particularly for PtX equipment and electrolysers. Transmission System Operators (TSOs) are urged to establish mandatory V-Q control requirements, focusing on connection levels. Moreover, the proposed solutions indicate that electrolysers could mitigate voltage issues in large power systems with appropriate regulation, and future grid codes should define contribution grades for inverters in multi-energy systems to ensure compliance and seamless integration.