SPP Interconnection: Find Power, Navigate the Queue, Secure Your Site
SPP plans transmission first, then identifies generator connection points and costs through an annual cluster study, targeting signed agreements within 180 days. Large loads of 50 MW+ follow separate rules, with curtailable bridge service while firm service is built. Explore the interactive guide, then use LandGate’s capacity and parcel data to find viable sites.
SPP Interconnection at a glance
Quick facts | SPP |
|---|---|
Who runs it | The Southwest Power Pool runs the grid and interconnection studies across the central U.S. and, since April 1, 2026, part of the Western Interconnection. FERC approves its rules. |
Governing rules | SPP’s FERC-approved tariff (Attachment AY for generators) and the Consolidated Planning Process Manual |
Generator study process | The Consolidated Planning Process, in effect since March 1, 2026. SPP plans transmission first, publishes planned interconnection locations and costs, then runs one annual 180-day cluster study with a single decision point. |
Queue window | December 15 to February 15 each year under the tariff. Dates for the current window haven’t been confirmed by SPP. |
Target timeline | 180 days from the close of the queue window to a signed agreement, compared with a historical median of 51 months |
Generator costs | Generators pay a GRID-C rate per kW toward planned transmission, with security rising to 100% of GRID-C at the decision point. Projects at unplanned locations also pay for some upgrades directly. Final rates are expected by the end of 2026. |
Large-load threshold | 50 MW or more connected above 69 kV, or 10 MW or more at 69 kV or below. SPP’s High Impact Large Load rules took effect January 15, 2026. |
Large-load study | About 90 days, with requests taken on a rolling basis |
Bridge service for large loads | Conditional High Impact Large Load Service (CHILLS): non-firm, curtailable service for up to 7 years while firm resources and upgrades are built. Effective July 1, 2026. |
Peak demand, for scale | 58.0 GW on July 27, 2026 |
Last updated | November 3, 2026 |
SPP Generator Interconnection Process
Generator interconnection,
step-by-step
Under its Consolidated Planning Process, SPP plans transmission first, then publishes where generators should connect and what they’ll pay. Generators apply in one annual window and go through a single cluster study with one decision point. SPP’s target is 180 days from window close to a signed agreement.
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Check planned locations and GRID-C rates. SPP publishes Planned Interconnection Locations and the GRID-C rates generators pay toward planned transmission before the queue window opens.
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Submit during the annual queue window. The window runs December 15 to February 15 each year. Applications need technical models, proof of 100% site control and financial security.
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Validation and cure. SPP reviews each request over about 60 days, and developers get 10 business days to fix flagged errors.
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Interconnection Cluster Study. SPP studies all requests together over 180 days. Projects at unplanned locations pay for some upgrades on top of GRID-C, so their costs are less certain.
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Commit at the decision point. Developers have 20 business days to commit by posting non-refundable security for 100% of their GRID-C, or withdraw.
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Facilities study. SPP and the transmission owner design the connection and set its costs, which the developer pays.
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Sign the agreement and build. The developer, transmission owner and SPP sign the interconnection agreement, then construction begins.
SPP Large Load Interconnection Process
Large Load interconnection,
step-by-step
SPP’s High Impact Large Load rules apply to loads of 50 MW or more connected above 69 kV, or 10 MW or more at 69 kV or below. Large loads reach SPP through their utility, and a curtailable bridge service lets them connect while firm service is built.
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Work through your utility. The utility serving the site requests transmission service from SPP. Smaller loads follow SPP’s standard process.
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Submit the request and scope it. Requests are taken on a rolling basis, and the study clock starts once the data is validated.
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Consider pairing new generation. New generation serving the load can use an optional fast-track study of about 150 days.
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High Impact Large Load study. SPP and the transmission owner study grid impacts and the local connection in about 90 days.
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Firm or conditional service. Loads with firm resources and upgrades ready take firm service. Others can take curtailable service for up to 7 years in the meantime.
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Meet ongoing requirements. Large loads must allow remote disconnection, install real-time monitoring and meet ride-through rules.
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Energize. The load comes online under firm service, conditional service, or both.
What's changed recently in SPP interconnection
Last updated November 2026
SPP rebuilt both of its interconnection paths in 2026. Generators now go through the Consolidated Planning Process, which replaced SPP’s old cluster queue, and large loads have their own framework with a curtailable bridge service. If your project is in SPP’s process or headed there, check which of these changes apply before the next queue window.
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January 15, 2026: SPP’s High Impact Large Load rules took effect for loads of 50 MW or more above 69 kV, or 10 MW or more at 69 kV or below.
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March 1, 2026: The Consolidated Planning Process took effect, replacing SPP’s old queue. FERC accepted it on March 13.
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April 1, 2026: SPP expanded into the Western Interconnection, and the transitional queue window for the first cycle opened.
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July 1, 2026: Conditional High Impact Large Load Service took effect, giving large loads non-firm, curtailable service for up to 7 years while firm service is built.
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October 2026: Draft GRID-C rates were reported to be awaiting SPP Board approval.
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Coming up: Final GRID-C rates by the end of 2026, the first signed agreements from the transitional cycle in spring 2027, and a new price-based curtailable service for large loads that SPP is developing.
How LandGate Helps with SPP Interconnection
Quickly and accurately determine the feasibility of a site in SPP using LandGate's nationwide data
Get your projects on the grid faster with reliable transmission data.
Choose the right location
SPP’s applications need proof of 100% site control, so picking a point of interconnection has to happen well before the window. Search parcels by criteria such as distance to a substation and available offtake capacity, and see available transfer capacity at transmission-level injection points to compare sites near SPP's planned locations.
Know the costs before you commit
At SPP’s decision point, security for 100% of GRID-C becomes non-refundable, and projects at unplanned locations pay for upgrades. LandGate’s automated offtake capacity studies show substation details, capacity results, limiting elements, and queue information, so you can spot upgrade risks before committing capital.
Find capacity at the right voltage
SPP’s large-load threshold drops from 50 MW to 10 MW at 69 kV and below, so voltage shapes which rules apply. LandGate maps the subtransmission grid with hosting capacity and available transfer capacity at the line level. Its Data Center Due Diligence Reports also rank the closest substations by available capacity to serve the site.
Lock down the best sites
SPP requires full site control at application and site control for most of the generator tie line at the decision point. LandGate pairs its grid data with proprietary landowner leads, nationwide ownership data and contact information, and a map-based CRM to help you find and secure the right parcels, including off-market properties.
