Operating Reserve Dimensioning Methodologies for Renewable Energy Aligned Power Systems

Over the last decade there has been a significant transformation in the electricity generation sector across the world, with the aim of reducing the environmental impact of electricity generation. Variable renewable energy (VRE) sources such as wind and solar photovoltaic have proven to be particularly popular in mitigating these environmental impacts. Increasing the penetration of VRE in the electricity generation mix will increase generation variability and uncertainty and can potentially introduce various technical challenges regarding the reliability of the power system network. Generation and demand must be in balance at all times for network reliability and operating reserves exist on the network to ensure system reliability during periods of imbalance. The risk exists that current "traditional" operating reserve dimensioning methodologies do not efficiently account for the increase in system imbalance variability and uncertainty as a result of increased VRE generation. This paper reviews the challenges associated with high VRE penetration networks and the caveats of current, "traditional" reserve dimensioning methodologies. Emerging, state-of-the-art methodologies in literature and in practice are reviewed to form a basis for future considerations in development of reserve dimensioning methodologies. The paper finds that transmission system operators (TSOs) of modern power systems with high VRE penetration in general are increasingly using probabilistic methodologies to dynamically dimension reserve requirements economically while reliably ensuring system adequacy.