A new report urges SPP to accelerate its interconnection process and reform market rules to allow greater buildout of energy storage.

The report notes that hundreds of battery storage proposals are sitting in the SPP interconnection queue, working through lengthy reviews. Few batteries are deployed in SPP now, but even 5 GW of capacity could boost reliability and reduce costs by a projected $7 billion over the next decade.

Aurora Energy Research issued the report Aug. 12. The American Clean Power Association (ACP), which commissioned it, called for SPP and state policymakers to:

• • accelerate interconnection for the quick-to-deploy technology;
  • reform market rules to generate price signals that incentivize storage development and recognize the reliability contribution of storage;
  • remove ambiguity on when storage must register as a transmission customer and how the associated charges are applied; and
  • streamline and clarify state and local permitting with uniform rules and standards to ensure faster, more certain project execution.

SPP did not return requests for comment for this story.

The RTO recently completed a yearslong effort to streamline and integrate its transmission and generation planning: On Aug. 5, its board of directors approved the Consolidated Planning Process and asked FERC to approve a March 1, 2026, effective date. (See SPP Celebrates Novel Consolidated Planning Process.)

Several statistics provided by Aurora, the Energy Information Administration and SPP itself point to the potential importance of storage:

• • SPP is the second-largest RTO in the nation geographically.
  • It is expecting the largest peak load growth of any RTO, reaching 69 GW in 2035 due to electrification of oil and gas extraction and data center buildout.
  • Thirty-eight percent of its 2024 energy production was from wind turbines.
  • Wind turbines are highly variable sources of power generation — in the past 30 days, hourly output nationwide ranged from 10,352 to 77,765 MWh.
  • The SPP interconnection queue is crowded with proposals for solar generation, which also is intermittent if more predictable.
  • SPP’s 2025 accredited summer battery storage capacity is 172 MW.
  • More than 25 GW of battery capacity proposals entered the SPP interconnection queue in 2024.

Aurora modeled two distinct scenarios in its report: one where restrictions limit 2035 battery capacity to 1.4 GW and the other where 4.7 GW of batteries are deployed, based on economic viability and assuming continuation of various policy reforms such as federal clean energy tax credits and SPP’s Consolidated Planning Process.

In 2035, prices during late-afternoon/early evening summer peak demand periods could be $1,141/MWh under the 1.4-GW scenario, compared with just $153/MWh under the 4.7-GW scenario.

Total system costs could be $7 billion higher in 2035, and electricity prices would climb 10.1% from 2029 to 2035 under the 1.4-GW scenario.

Also over the next decade, the report forecasts growing net hourly load ramps due to expected increases in population and solar generation.

Small ramps will decline in number, the authors say, but large ramps will become more numerous: By 2030, more than 700 hours a year will require a ramp greater than 4 GW, compared with 37 hours in 2020.

A storage fleet larger than 5 GW is critical to grid reliability and cost savings, the report states.

It cites the performance of battery energy storage systems in ERCOT, where 15-minute battery discharges as high as 1.97 GW prevented load shed during several high-stress periods in the late summer of 2023.

“Evening power prices could be 80% lower in SPP if the region can build out the battery storage central states need to ensure reliability,” Noah Roberts, ACP vice president of energy storage, said in a news release. “As power demand surges, battery storage is one of the fastest and most effective ways to strengthen reliability and lower electricity bills. Grid batteries deliver significant cost savings for families and businesses, and provide the reliability needed to power our economy into the future.”