Decarbonizing Power Systems: The Roles of Wind Power and Energy Storage in Phasing out Fossil Fuels

Abstract

The rapid deployment of renewable energy and energy storage technologies is driving the decarbonization in power systems, accompanied by the retirement of fossil-fuel power plants. While this transition reduces emissions, it also introduces challenges related to system reliability, cost, planning, and operation. To support the decarbonization of power systems, it is essential to investigate the multifaceted roles and impacts of renewables and energy storage and develop strategies to facilitate their integration while phasing out fossil fuels.

This thesis first develops analysis frameworks based on optimization models to study the interactions between wind power, energy storage, and conventional generators in energy and ancillary services markets under the influence of decarbonization policies. The analysis focuses on understanding the mechanisms driving short- and long-term changes in emissions, costs, and fossil-fuel retirements. The results highlight that unexpected emissions outcomes can arise due to the co-optimization of energy and frequency regulation under decarbonization policies, leading to costs and profits that influence capacity retirement and additions over time. These findings emphasize the need for policymakers and system operators to account for these dynamics and align technological deployment with decarbonization objectives.

This thesis further examines strategies for replacing fossil-fuel generation with wind power and energy storage. Specific attention is given to systems constrained by factors such as remoteness, insufficient infrastructure, and other limitations. Three strategies - replacing exact generation, replacing at least exact generation, and replacing total energy - are simulated using a power system planning and economic dispatch optimization model. The results highlight the trade-offs among investment costs, operational changes, and energy security, emphasizing the importance of strategic decision-making by investors and system operators to adopt tailored methods.

Finally, this thesis proposes optimization models for the planning and operation of green hydrogen plants with energy storage and hydrogen storage systems. By replacing traditional gas-fueled methods, wind power and energy storage have the potential to decarbonize other economic sectors through the production of green hydrogen. The thesis identifies key trade-offs between hydrogen storage and battery storage in terms of meeting demand and managing component degradation. It also examines the impacts of different emissions accounting policies to ensure that green hydrogen remains ``green" when connected to power grids. The findings highlight the contrasting and complementary effects of batteries and hydrogen storage, emphasizing the need to optimize their capacities to enhance system performance, cost-efficiency, and compliance with emission policies.

By addressing these interconnected challenges, this thesis contributes to understanding the mechanisms driving the complexities in the integration of new technologies and the retirement of conventional ones. It also contributes to proposing optimization models to facilitate the deployment of renewables and energy storage, and link power systems decarbonization to broader energy sectors through green hydrogen. The thesis provides insights into the system design, capacity investment, market structures, and policy interventions required to achieve a reliable and cost-effective energy transition.