Ancillary services capability of grid-connected renewable energy systems

Abstract

Renewable energy sources are rapidly expanding their share in the global electricity mix, driven by the need to reduce carbon emissions and enhance energy security. However, the variability and uncertainty of renewables pose significant challenges for the reliable and efficient operation of power grids, which require stable and balanced supply-demand dynamics. Ancillary services, which are the supplementary services that support the basic functions of the grid, have emerged as a critical means to address these challenges and optimize the integration of renewables. This thesis aims to investigate the potential and challenges of renewable-based ancillary services, with a focus on photovoltaic (PV) and wind power systems. The study employs a multi-disciplinary approach that combines technical, economic, and regulatory aspects, and incorporates both quantitative and qualitative methods. The thesis starts by reviewing the literature on renewable ancillary services, and identifying the main types, requirements, and benefits of these services. Then, it presents a detailed analysis of the technical characteristics and performance of PV and wind power systems in providing ancillary services, based on simulation models and case studies. The analysis covers a range of ancillary services, including frequency regulation, voltage control, and ramping support, and evaluates the effectiveness and limitations of renewables-based solutions. Finally, the thesis draws conclusions and recommendations for future research and practice in the field of renewable ancillary services. The study highlights the importance of holistic and integrated approaches that consider the technical, economic, and regulatory aspects of renewables integration, as well as the need for coordinated efforts among different stakeholders. The thesis also identifies the challenges and opportunities for further improving the reliability and sustainability of power grids with renewables-based ancillary services.