Development of a Pricing Model for the Reactive Power Supply via Statcom Capability of a Real PV Power Plant

Abstract

The German Energiewende policy mandates the gradual decommissioning of conventional power plants, shifting the responsibility of reactive power (Q) provision to renewable energy sources. This paper evaluates the economic benefits and impact on inverter lifespan of extended Q provision, developing a pricing model that considers both dispatch and reserve costs. The study examines the provision of Q outside the technical connection rules of a utility-scale PV power plant in the transmission grid. Utilizing a detailed simulation model of a real extra high voltage PV park with 350 MW installed power, cost components are presented, valuation approaches formulated, and their application in the transmission grid examined. The basic valuation approach considers both plant-specific and external costs, focusing on active power losses and inverter wear. The analysis shows that relative losses (MWh/Mvar) in the park vary due to dispatch patterns, representing the highest cost sensitivity. Our results underscore the importance of these factors in determining the Q price. The findings indicate that additional Q can be provided without structural changes to the inverters, but economic viability depends on appropriate compensation mechanisms. A field study investigation of the simulative observation is recommended for further validation and is done in the research project Q-REAL.