Solar and Storage Integration in the Southeastern United States: Economics, Reliability, and Operations

Solar energy has the potential to be a core energy resource for the southeastern United States. To better understand the implications of higher levels of solar PV (27%-43% of total generation capacity) and electricity storage (13%-49% of peak load) would affect electricity system reliability, costs, and operations in the U.S. Southeast, this study sought to address two main questions. First, how would higher levels of solar PV and electricity storage impact the costs, reliability, and operations of electricity systems in the Southeast in 2035? Second, at different levels of solar PV and electricity storage, what are the benefits of operational coordination among utilities in the Southeast, through more efficient regional dispatch and sharing operating reserves?

To answer these questions, the study used detailed capacity expansion and dispatch modeling to develop and examine 15 scenarios with different levels of solar PV, electricity storage, and operational coordination, focusing on the year 2035. The study also evaluates the benefits of operational coordination among utilities through more efficient regional dispatch and reserve sharing, at different levels of solar and storage. The study focuses on five balancing regions that cover Alabama, Georgia, Kentucky, North Carolina, South Carolina, Tennessee, and parts of Mississippi and Missouri.

The analysis in the report is based on five national, cost-optimized resource portfolios that were developed using NREL’s Renewable Energy Development System (ReEDS) model and are publicly available for download under Related Files. The resource portfolio file includes installed capacity by technology and balancing area (entire continental U.S.) for each of the five portfolios, which correspond to five scenarios that have different solar cost, storage cost, and, in two scenarios, carbon tax assumptions. The report provides detailed descriptions of the assumptions behind each scenario.

A webinar discussing this study, recorded on October 3, 2024, can be viewed here.