The Indiana Utility Regulatory Commission (IURC) retained LBNL to study the techno-economic impact of distributed energy resource (DER) adoption in the Indiana power system. For this study, LBNL developed a framework that employs a variety of methods to assess three components: the physical impact on distribution, transmission, and generation capacity; the economic and rate impact on customers; and the reliability and resilience impacts on the distribution system.
LBNL used utility data from ~2800 distribution system feeders to determine representative feeders that could be used for in-depth analysis. We ran over 3400 simulation-hours on these representative feeders using distribution system simulation software Cymdist, covering a diverse array of DER adoption and net demand scenarios, over the short and long term (2025 and 2040). Feeder-level net demand was scaled up to the state-level and input into a capacity expansion and production cost models to assess the transmission and generation impacts of DER adoption levels and calculate rate impacts. Finally, LBNL used half a million historical outages in Indiana to simulate the impact of DER storage on reliability and resilience.
The report finds that voltage regulation, line loading, and energy losses impacts in distribution systems are seldom and largely occur in the most stringent stress-test scenario. Generation impacts account for roughly 80% of the cost impacts in most scenarios. Overall, rates are higher for all DER adoption scenarios compared to the base case given the need to cover utility fixed costs with lower sales, or the need to provide substantial peak capacity to support unmanaged EV charging.