Southwest Power Pool Details Progress in Clearing Interconnection Study Backlog

by Paul Ciampoli
APPA News Director
July 13, 2023

The Southwest Power Pool on July 12 reported that it has reached the halfway point in clearing the backlog of requests to study the impacts of connecting new generating resources to the region’s power grid.

Over the last several years, overwhelming interest in building new generation – primarily from developers looking to construct wind and solar farms – led to longer than usual timelines in SPP’s study processes.

In response to record growth in its interconnection queue, over the last three years SPP said it has worked to make improvements to the quality of its study models and processes.

In January 2022, the Federal Energy Regulatory Commission approved tariff revisions designed to simplify and reduce SPP’s study timelines.

SPP said it has also taken steps to improve model accuracy, such as posting models and draft interconnection study results for review before the final results and using fuel-based dispatch: enhancing planning models so that they simulate the dispatch of generation more like SPP’s real-world, day-ahead market while identifying transmission needs resulting from the interconnection of new generators.

SPP’s “Definitive Interconnection System Impact Study” (DISIS) process utilizes a three-phase approach to evaluate the impact of the proposed generation to the transmission system and provides a report and decision point window for each phase.

Since the implementation of the backlog mitigation plan, SPP has completed five DISIS Phase One analyses and two Phase Two analyses. The remaining studies are currently on track to be completed by the end of 2024.

SPP said it has seen an exponential increase in installation rates over the last nine years adding a record amount of generation to the resource pool. Within that timeframe, an average of 2,800 MW of new wind generating capacity has been added to our region year over year.

“As a result of the success of the backlog mitigation plan, interconnection customers have executed agreements to add over 14.5 GW of new generation to the system over the next four years,” SPP said.

There are 561 active requests remaining in the SPP interconnection queue, of which approximately 220 of them were submitted in 2022. These requests represent 112 GW of new generation—108 GW of which are renewable, storage or hybrid resources.

To facilitate flexibility for generation requests, SPP has performed more than 27 modification studies to analyze generation changes due to technological advancements and supply chain issues. Several other studies have analyzed the replacement and optimization of existing granted interconnection service with new generation.