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You asked. We answered in a part I blog post. You asked more questions. We answered in this part II blog!
Browse the common questions that market participants have ahead of the Electric Reliability Council of Texas (ERCOT) launching the Real-Time Co-Optimization Plus Batteries (RTC+B) market changes on December 5, 2025.
More Frequently Asked Questions
Pricing, ASDC, and Virtual Participation
Q: What is the new price cap, and when will it begin?
A: Under RTC+B, the current system-wide offer cap (SWCAP) of $5,000/MWh is being replaced by a day-ahead system-wide offer cap (DASWCAP) equal to $5,000/MWh and a real-time system-wide offer cap (RTSWCAP) equal to $2,000/MWh. This replacement will happen at go-live. The system-wide offer caps are not to be confused with price caps. It is possible for the LMP to exceed offer cap prices, for example, due to extreme congestion, like we saw earlier this year as outlined in this Yes Energy blog post. However, under RTC+B the system lambda used to determine LMPs and the real-time MCPCs (ancillary service clearing prices) will be capped at the effective Value of Lost Load (VOLL), which is currently set to the DASWCAP of $5,000/MWh.
Q: Are all qualified scheduling entities (QSEs) able to submit virtual ancillary service offers or only those QSEs representing physical assets?
A: Yes. Any registered ERCOT QSE is able to participate in virtual ancillary service trading; however, ERCOT has specific credit requirements for virtual bidding that must be met.
Q: Regarding virtual ancillary service products post RTC, non-physical resources can only offer, not bid, correct?
A: Yes, that is correct!
Q: What impact is RTC+B expected to have on ERCOT reports?
A: There will be over 100 ERCOT reports impacted by RTC+B, ranging from new reports added (25), reports modified (28), and reports retired (17). Regarding the data impact in Yes Energy, we will be keeping the spreadsheet linked in the ERCOT RTC+B FAQ article on our help system up to date with all data impacts.
Q: How will this market update affect load serving entity (LSE) collateral needs?
A: Collateral requirements are changing to capture the additional risk of ancillary service (AS) virtual offer activity in the DAM, and the changes may impact you. ERCOT released a market notice with more details on November 5, 2025, citing two key credit reports with changes. However, these reports are certified, and as a result, Yes Energy is unable to collect them.
Batteries (ESRs) and Telemetry
Q: How will ERCOT RTC+B impact battery energy storage system (BESS) node pricing in the DA and RT markets?
A: See below for the potential short-term and long-term impacts of RTC+B on BESS node pricing in ERCOT.
Potential short-term impacts:
- This market change may cause increased volatility in pricing, creating opportunities for participants who are ready and actively participating at go-live. These disruptions include the complete overhaul of the RT clearing engine for pricing and dispatch, introducing co-optimization, adding new AS markets into the RT for the first time, and introducing virtual AS to the DAM.
- From the perspective of batteries, the volatility at market launch could introduce opportunity to capture disruptions in the daily price spreads for charging and discharging.
Potential long-term impacts:
- Co-optimization in the RT market is expected to result in more optimal, least-cost dispatch, which is expected to produce reduced RT energy prices on average over time (compared to the non-co-optimized scenario).
- Virtual AS participation in the DAM could introduce additional liquidity and market competition, contributing to greater price convergence between the DA and RT over time, i.e. reduced DART spreads
Q: What are potential changes in bidding behavior that energy storage resources (ESRs) may experience?
A: For ESR owners, the volatility at market launch could introduce an opportunity to capture disruptions in the daily price spreads for charging and discharging. Virtual AS participation in the DAM could introduce additional liquidity and market competition, contributing to greater price convergence between the DA and RT over time, i.e. reduced DART spreads.
SCED Operations and Market Mechanics
Q: When ERCOT RTC+B goes live, and the supplementary ancillary service market (SASM) goes away, will ERCOT move undeliverable ancillary services over to another generator with available capacity and then claw back the day-ahead ancillary service payment for the short generator? Is the same true for loads carrying ancillary services?
A: With RTC+B, ancillary services in the day-ahead market will be financially binding only. For both generation and load resources, ancillary service offers will be paid the day-ahead clearing price and settle any imbalances in the RT market.
More Resources
Want to learn more about the ERCOT RTC+B Program? Browse our resource hub or download the on-demand webinar.
Have a question not answered here? Reach out to support@yesenergy.com.
About the author: Portia Gilman manages the Market Monitoring Team, a group that stays abreast of the North American energy markets so you don’t have to. The team serves internal and external clients with regulatory market knowledge and subject matter expertise on the impacts to Yes Energy’s clients, data, and the energy industry as a whole. Previously, Portia was an analyst for ISO New England’s internal market monitoring group for over six years, specializing in compliance, price formation, SCED dispatch, and capacity market economics.
