The application of energy storage technologies for grid integration of renewable systems: A focus on li-ion batteries for wind turbine generators

Hydrocarbon-based power production has been a global concern during the past
decade not only due to its adverse impact of greenhouse gas emissions, but also accounting
for the inevitable depletion of finite traditional energy resource reserves. This, coupled with
the ever-increasing demand for electrical energy, has prompted a widespread shift towards
renewable energy sources (RESs) such as solar, wind, and geothermal power. The aim is to
provide reliable, clean, and sustainable energy to enhance overall life quality. However, the
adoption of RESs faces challenges, particularly in dealing with their inherent variability and
intermittent nature, especially when integrated into vulnerable grid systems. Such integration
can negatively affect the security, reliability, and quality of grid regulation. To address these
issues, energy storage technologies (ESTs) have emerged as promising solutions, storing
excess energy during periods of abundance, and making it available on demand. Despite the
existence of various grid-scale ESTs, there is a lack of comprehensive assessments of their
advantages, disadvantages, and application potentials. Additionally, the progress in
integrating ESTs into grid systems has not kept pace with advancements in both EST and
RES technologies. This thesis focuses on the systematic selection, evaluation, and integration
of ESTs into grid-connected wind turbine generators (WTGs). The main contributions of this
thesis begins with the development of a holistic approach which is dynamic, scalable, and
applicable over time for selecting and evaluating ESTs among various options based on
technical, economic, and environmental criteria. Through the developed method Li-ion
batteries was identified as the most suitable EST for the studied application. Furthermore, the
contribution includes development of a model to simulate and evaluate the performance of
grid-connected WTGs under different operating conditions. To this end, this study
demonstrates the suitability of Li-ion batteries for efficient grid integration of doubly fed
induction generator ( DFIG ) and their role in smoothing the output power of grid-connected
systems in MATLAB/Simulink environment. The outputs provide valuable insights into the
selection, application, and impact of adopting ESTs, particularly in low-income economies
where non-technical assessments, such as cost considerations play a significant role.