The Yes Energy team is preparing for Southwest Power Pool (SPP) to extend its Regional Transmission Organization (RTO) into the Western Interconnection, a historic move that makes SPP the first RTO to operate organized wholesale markets across both the Eastern and Western Interconnections.
SPP’s RTO Expansion (RTOE), launching April 1, 2026, raises important considerations across trading, operations, and risk. While the team readies our solutions to help customers navigate this major market shift, we also compiled answers to the most common questions to help you understand what’s changing and the market impacts.
Your Frequently Asked Questions
Data Availability
1. Are the new RTOE LMPs available in Yes Energy prior to going live on April 1, 2026?
Yes, test data is available in our products from the following four reports: DA LMP by Settlement Location, DA MCPs, RTBM LMP by Location, and RTBM MCPs.
2. Given the separate BAs, should we expect the MEC in SPP West and East to be different most of the time?
The East BAA, reported by the ISO as “SPP,” maps to an existing Yes Energy objectID= 10017060648 (name= ‘SPPISO-East’). The West BAA, reported by the ISO as “SWPW,” maps to an existing Yes Energy objectID= 10019234935 (name= ‘SPPISO-Westt’).
The MECs will relate to each other based on the status of the West DC Ties connecting the two BAAs. When the DC Ties have available capacity (unconstrained), SPP’s single market optimization will simultaneously determine flows and dispatch across both networks. The same marginal resource influences the marginal cost to serve the load in both BAAs.
If the DC Ties have no available capacity (constrained), SPP's single market optimization will economically stop scheduling power to flow across the interconnections, the MEC will decouple, and the market optimization will find the generator from each specific BAA to serve the next increment of load.
Though SPP will calculate separate Marginal Energy Components (MEC) for the East and West BAAs, the two will often be economically linked. The 310 MW limited capacity of the two DC Ties is expected to be a frequent constraint.
3. Will there be any more RTO-wide forecasts or just separate east and west forecasts?
For many reports (wind/load forecasts, fuel mix, etc.) SPP is no longer posting the system-wide object and is just posting the data at the BAA level (called SPPISO-East and SPPISO-West in our products). Yes Energy plans to preserve the SPPISO object for continuity purposes by summing “SPPISO-East” (objectID= 10017060648) and “SPPISO-West” (objectID= 10019234935) post cutover.
An SPPISO object (i.e. an ISO-wide object) is preserved for all “actuals” data. The system-wide object specific to forecast data is being worked on by our development team and will be available by the end of the day (March 31). This means that before April 1, 2026, the SPPISO object will show data for SPP East, and after April 1, 2026, the SPPISO object will show data for East and West. Please keep an eye out for additional details in the Release Notes in the Help Center.
4. Do Yes Energy customers need an additional subscription to access SPP RTOE data?
The SPP RTOE data is available under the existing SPP Trading Region subscription in Yes Energy.
5. Will the SPP RTOE data fall under SPP access from a Yes Energy subscription standpoint?
Yes.
General Questions
6. How does the MTE testing environment function?
SPP coordinates structured and unstructured testing within its Member Test Environment (MTE) before large market design changes that involve executing specific base-case scenarios to simulate actions that will occur in the new settlements process.
The purpose of the MTE for the RTO Expansion is to run SWPW simulations to enable SPP, Transmission Customers (TCs), and Transmission Owners (TOs) to practice, validate, and refine the processes and systems intended for the RTOE before its production launch. We use this test data to make sure we are collecting and ingesting the format of the new reports accurately.
7. How do you expect the change to impact power prices in SPP as well as the amount of wind curtailment?
The new West Hub will have many fewer wind resources in its supply stack than SPP East. Therefore, SPP West is expected to have a real-time price premium over the North and South Hubs, leading to fewer prolonged low-price periods than the East. RTOE will create economic opportunity for SPP East wind resources by spreading wind generation across a larger area, allowing SPP to reduce local curtailment (albeit limited by DC Tie capacity). A new Western Trading Hub facilitates better hedging against wind-driven negative prices in the expanded footprint.
8. Where can people access information about SPP RTOE on SPP's website?
The primary page for SPP RTOE on the SPP website is https://www.spp.org/western-services/rto-expansion/.
Market Design
9. Will the market rules for SPP West resources differ from those in the rest of the SPP footprint?
No. However, you should be aware of the SPP's mechanism for managing market power, which involves "Frequently Constrained Areas" (FCA). When an FCA is binding, energy offer curves are capped at 17.5% above the mitigated energy offer curve prices.
Due to the limited transfer capability across the DC Ties, we can expect all resources in SPP West to qualify as pivotal suppliers, unlike SPP East where this binds for a small minority. SPP West resources will face a binding FCA, capping energy offers at 17.5% above mitigated prices. The high shift factors in SPP West indicate that even smaller resources will significantly impact specific flowgate constraints due to their substantial locational load weighting.
10. How is SPP going to manage the tie interconnections between west and east; will anything change on that front? Substantial congestion between regional interfaces? Will there be LTRC and TCRs across those lines?
SPP will continue to utilize its market optimization but will now be used to manage the asynchronous flow across the West DC Ties to dispatch the most economical resources for East and West BAAs using a single market optimization process. Each West DC Tie will be modeled in the market software as a linked withdrawal/injection pair joining the two BAAs.
The Security Constrained Unit Commitment (SCUC) will optimize the direction of the flow across the ties. Subsequently, the Security Constrained Economic Dispatch (SCED) will determine the optimal volume of the flow.
See more information about the LTRC and TCRs changes in questions four and five .
11. How will import/exports be settled? Will all POD adjacent to PSCO be settled at PSCO LMP?
PSCO's service territory will be almost entirely contained within the expanded SPP footprint, making its monitoring important.
PSCO Interface location is an aggregate settlement point representing the weighted average of multiple interconnection points. Therefore, not all adjacent points of delivery will settle at this interface price. Virtual bidding/offering on the interface settles at this aggregate price.
A key dynamic to watch is the impact of transmission congestion on individual paths that make up the aggregate interface PNode. If the lines into PSCO become constrained, the PNodes on the SPP side of the border will likely experience a lower (or negative) Marginal Congestion Component (MCC). Simultaneously, the "internal" PSCO price will remain high, though this internal price cannot be traded directly in SPP.
12. How will the interfaces work? Will it be similar to the East?
The Security Constrained Unit Commitment (SCUC) will optimize the direction of the flow across the ties. Subsequently, the Security Constrained Economic Dispatch (SCED) will determine the optimal volume of the flow.
13. With SPP Markets+ now overlapping with CAISO EDAM, will participants who previously participated solely in SPP have the option to register under CAISO EDAM as well? Can they choose one or the other or possibly register for both?
Market participants will have to decide between participating in CAISO EDAM/EIM, SPP Markets+, or SPP ISO. Customers cannot participate in both CAISO EDAM and SPP or CAISO EDAM and SPP Markets+.
Physical Trading
14. Will there be no more e-tagging allowed across the tie?
Correct, physical e-tagging will no longer occur across the ties and will be scheduled from market optimization. See question 11.
TCR/FTR Market Impacts
15. Has a TCR auction for the RTO Expansion area already happened? Is there real data for this already?
No, the Transmission Congestion Rights (TCR) auction has not yet happened for the SPP RTO Expansion area in the West.
The first TCR auction reflecting the RTO Expansion data will be the Annual TCR auction, with results published on May 22, 2026. Internal SPP East’s source-to-sink paths will operate like SPP TCR market but with a distinct nomination cap reflecting system capabilities. Cross-DC Tie allocation will transition over the first four years, automatically awarding rights to existing holders for stability. After this period, TCR participants can nominate and allocate cross-interconnection paths like any other source-to-sink path, meaning economic bids for these paths won't be reflected in TCR market data for four years.
16. How is the TCR market changing with this new tie?
The TCR market rules will remain consistent for paths that are contained in each BAA. The nomination cap will be set by SPP West capabilities, sharing the standard business-as-usual procedure for TCRs as SPP East operations.
However, the source-to-sink paths that cross the DC Ties will undergo a four-year transition period. During this time, congestion hedging will be based on long-term Transmission Service Rights (TSRs) and settled as an option. The holders of these rights will be automatically awarded. So we will not have offer/bid data for these specific paths that will not reach the TCR market until after the four-year transition period.
17. Are the pricing points in the west available to market participants in the east to use for the ARR/TCR purpose?
Yes, LMP data for nodes in the west will be available to market participants in the east for ARR/TCR purposes.
18. When is the first TCR auction that will reflect the new RTOE locations?
The SPP West footprint and three internal DC Ties will first show up in the annual ARR allocation process, which opens on April 1, 2026. RTO Expansion-related FTR data will first show up in the Annual TCR/FTR auction (results published May 22, 2026).
Virtuals/Trading
19. How does this affect DA and RT bilateral trading and e-tags for physical trades between counterparties?
Physical trading based on e-tags is no longer permitted for sinks or sources located within the SPP West Balancing Authority Area.
Bilateral trades that were previously path-based are now converted into financial arrangements that settle against the DA or RT LMP.
SPP West market participants can submit DA bids and offers, with settlement based on the LMP difference. Any deviations in real time will settle at the RT LMP.
20. Is DA bidding available? If not, when? Is the DA segregated from the current market? Is this a separate portal?
Yes, there are approximately 298 new tradable nodes in SPP West. They will be virtually traded exactly how SPP East is traded today.
21. How many new tradeable, settlement nodes are there for SPP RTOE?
There are approximately 300 new tradable nodes in SPP West.
22. What is the impact of SPP RTOE on the virtual market? When can traders place virtual trades on the SPP West nodes?
There are about 298 new tradable virtual nodes for SPP West. These nodes will be tradable in the virtual market March 31 for the first operating day April 1. The new tradable nodes for SPP West can be found here: https://portal-mte.itespp.org/pages/da-lmp-by-settlement-location (filter BAA=SWPW).
23. Where can we find the list of new virtual tradable nodes in the west?
The new tradable virtual nodes for SPP West can be found here: https://portal-mte.itespp.org/pages/da-lmp-by-settlement-location.
24. Will there be new tradeable virtual nodes associated with the seven WEIS members joining SPP RTOE?
Yes, there are approximately 298 new tradable nodes in SPP West. They will be virtually traded exactly how SPP East is traded today.
