The Southwest Power Pool (SPP) is emerging as the one of the fastest-moving markets for U.S. battery storage, with 10.7 GW of capacity expected online by 2030 - a sharp rise from today’s 300 MW.
Most of this new capacity is clustering in Oklahoma, Kansas, and Texas, where developers are taking advantage of surplus grid capacity and renewable co-location to accelerate delivery and cut interconnection timelines.
So how has SPP reached this point - and which developers are leading the region’s first large-scale storage buildout?
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Executive Summary
- 10+ GW of battery storage is expected to reach commercial operation by 2030 in SPP.
- 4.8 GW of projects already hold signed interconnection agreements (GIAs) - clustered in SPP’s bottom half.
- Oklahoma anchors the region’s buildout, leading with 2.3 GW in late-stage projects - nearly half of SPP’s near-term pipeline.
- Two-thirds of late-stage projects exceed 100 MW, and the average duration is four hours. This reflects developers’ focus on revenue certainty through SPP’s Resource Adequacy market.
- Eolian and NextEra Energy dominate late-stage portfolios, with 1480 MW and 965 MW of announced projects in late-stage development.
SPP is projected to have 10+ GW of battery capacity by 2030
The buildout of batteries is expected to accelerate toward 10.7 GW by 2030, with the bulk of projects expected to come online in the late 2020s.
This total represents about 20% of the region’s queued BESS capacity, based on stage-weighted completion rates and development timelines. The projection mirrors battery deployment in mature markets such as ERCOT and CAISO.
Out of that total, around 300 MW are already operational, with 2.9 GW expected by 2027 and a sharp inflection in 2028–29 as late-stage projects move into construction.
Most of that growth will come from projects already in advanced development, concentrated heavily in the southern half of SPP.
Southern SPP leads buildout with 95% of late-stage projects
Out of SPP’s 10.7 GW expected battery buildout by 2030, 4.8 GW of projects have signed Generation Interconnection Agreements (GIAs). This is the stage most likely to reach construction in the near term.
These late-stage projects are concentrated almost entirely (95%) in the southern half of the footprint, where interconnection capacity and renewable co-location potential are strongest.
Oklahoma leads development with 2.3 GW, followed by Kansas (1.1 GW), Texas (0.6 GW), and Nebraska (0.4 GW). Smaller pockets appear in New Mexico (0.1 GW) and Arkansas (0.07 GW). Meanwhile, North Dakota (0.24 GW) is the only northern state with late-stage projects.
Why are batteries clustered in Oklahoma?
Oklahoma has become the center of battery energy storage development in SPP. This is because it combines strong grid access, renewable overlap, and faster interconnection options.
The state hosts several Surplus Interconnection sites, allowing new batteries to share existing grid capacity instead of waiting for costly upgrades.
At the same time, demand growth from industrial and data center loads is tightening local Resource Adequacy margins. This is prompting load-serving entities to seek flexible capacity closer to demand centers.
Recent SPP queue reforms and major transmission investments across Oklahoma and Kansas have further reduced connection risk. As a result, these southern zones are becoming the most attractive for developers aiming to reach commercial operation before 2030.
Developers scale up with larger projects across key southern clusters
Beyond location, project size is becoming a defining feature of SPP’s storage buildout. Nine late-stage batteries of 200 MW or greater are now under development. This is a clear indication that developers are prioritizing scale to improve economics.
The Southeast cluster, covering eastern Oklahoma, Arkansas, East Texas, and Louisiana, leads in project count (18) and size (2.2 GW), including three 200 MW systems in advanced stages.
SPP Central, spanning Kansas and western Missouri, follows with roughly 1.1 GW of late-stage capacity across eight projects, including the Garner Battery Storage project (425 MW). This is the largest battery in SPP’s current queue, expected to be operational by 2030.
In the Southwest, developers in north-western Texas and New Mexico are progressing smaller systems (36–200 MW) across six projects, typically near renewable generation hubs. Nebraska and the northern cluster round out the list, with batteries ranging from 11 MW to 200 MW across five projects.
100+ MW batteries are the preferred choice in SPP
Developers in SPP are prioritizing medium- to large-scale systems, with 65% of late-stage capacity coming from batteries rated above 100 MW.
Most late-stage battery capacity (52%) comes from projects within the 101–200 MW range. Only two projects have rated powers above 200 MW, representing 13% of the late-stage capacity. Additionally, systems between 51 and 100 MW make up another 30% of total capacity. Meanwhile, smaller projects below 50 MW account for 5%.
This contrasts sharply with ERCOT, where nearly 60% of operating batteries are below 50 MW. SPP’s pipeline, by contrast, suggests a market skipping the “pilot phase” altogether.
Developers in SPP are starting with large capacity sites, a sign of growing confidence and favorable project economics.
One reason for this is experience. Many private developers active in SPP have already deployed batteries in ERCOT or CAISO. This gives them the technical and financial comfort to build bigger from the outset.
The other reason is cost. The fall in lithium-ion prices has made large-scale batteries cheaper to deploy than they were when ERCOT and CAISO’s markets first emerged.
Eolian and NextEra lead SPP’s late-stage storage pipeline
A total of seven developers with late-stage battery projects have been identified in SPP’s interconnection queue.
Eolian and NextEra Energy together account for more than half of the region’s advanced-stage capacity, underscoring their early-mover position as SPP’s buildout accelerates.
Eolian leads with 14 projects totaling 1680 MW, ranging from 10 to 200 MW each. Most are located in Oklahoma and Nebraska, with one 72.5 MW system in Arkansas, and another 50 MW system in Missouri. Four of Eolian’s projects sit within the Surplus Interconnection Cluster. This allows them to reuse existing grid capacity and cut interconnection timelines in half.
NextEra Energy follows with nine projects totaling 965 MW, mainly in Oklahoma and Texas, and one 170 MW project in North Dakota. Four of the projects are already operating, which makes NextEra Energy the developer with the biggest operating portfolio. The projects range from 10 to 200 MW each, and all of them are part of the Surplus Interconnection Cluster, co-located with existing solar assets to lower study costs and accelerate delivery.
Other participants include Invenergy and Tenaska, each developing a 95 MW project in Kansas. Acciona Energy is developing a 50 MW battery also in Kansas, Xcel Energy a 36 MW project in New Mexico, and Today’s Power has two 6 MW batteries in Arkansas.
Around 2 GW of late-stage capacity remains undisclosed.
The dominance of a few large developers mirrors patterns seen in ERCOT and CAISO, where early access to interconnection rights has proven decisive. In SPP, those leveraging Surplus capacity and hybrid co-location strategies are emerging as the region’s leading players.
What’s next for SPP developers
SPP’s storage market is entering a defining phase. Developers that secure interconnection rights early - particularly through the Surplus Interconnection Cluster - will be best positioned to benefit from new Resource Adequacy needs and rising peak spreads.
As more projects reach commercial operation, southern SPP is set to become one of the fastest-growing battery hubs for the second half of this decade.
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