A Technoeconomic Analysis of the Challenges and Opportunities in Integrating Inverter-Based Resources into the Electrical Grid

Integration of inverter-based resources (IBRs), primarily wind, solar, and battery storage, into the electrical grid has increased yearly in the United States, driven by cost reduction, technological advances, and policy. As grid operators integrate these fundamentally different devices into the grid, there has been a paradigm shift in how they plan and operate the electrical grid. However, grid operators use traditional methods and generators to work around IBRs, rather than taking advantage of their operating capabilities. This thesis proposes solutions to three of the most pressing issues related to integrating IBRs into the electrical grid: voltage stability, frequency support, and transmission expansion. In Chapter 2, I evaluate whether solar photovoltaic (PV) inverters improve nighttime voltages on the grid and how much that operation costs compared to the traditional solution of installing voltage compensators, such as a static synchronous compensator (STATCOM). I find that nighttime voltages on the grid improve when PV inverters provide voltage support at night, reducing system costs by millions of dollars, or 4- 15 times less costly than installing a STATCOM. In Chapter 3, I examine if IBRs can provide fast frequency response (FFR) to support grid frequency and replace system inertia. I introduce an FFR requirement in a unit commitment and economic dispatch (UCED) model to assess the competitiveness of wind, solar, and battery storage in the Electric Reliability Council of Texas (ERCOT) ancillary service market. I find that under low IBR penetration, an FFR requirement increases energy prices by 7%, but that cost goes down to zero under high IBR penetration. In Chapter 4, I investigate whether incorporating long-term load forecast (LTLF) uncertainties can affect the production cost savings differences of transmission expansion projects that accommodate more IBR penetration on the grid, which is a key factor in transmission expansion decision-making. I develop a distribution of LTLF errors for ERCOT’s eight regions that I use in an optimal power flow of a nodal ERCOT model to gauge the effect of LTLF uncertainties on production cost savings of three transmission expansion improvement options. The heterogeneity of the LTLF errors reduces the production cost savings differences between the three options by millions of dollars, making two of the options indistinguishable.