What to know about ERCOT’s new RTC+B program

While many of us wait until January to start our New Year’s Resolutions, the Electric Reliability Council of Texas (ERCOT) began its 2026 glow-up a little early.  

Last week, Texas’ independent system operator officially launched its long-awaited Real-Time Co-optimization plus Batteries (RTC+B) program in what’s the biggest change to the market in 15 years. The new structure integrates ancillary services into the real-time market rather than the day-ahead market, allowing ERCOT to simultaneously optimize them with energy.  

“RTC+B is a win for the ERCOT energy market overall,” Portia Gilman, a market monitoring manager at energy market analysis firm Yes Energy, told ESS News. By co-optimizing energy and ancillary services together instead of addressing them separately, she explained, the program will likely result in “more optimal, least-cost dispatch across the system.” 

In practice, this could look like falling average energy prices on the real-time market compared to the previous, non-co-optimized structure. Gilman noted that she also expects liquidity and competition in the day-ahead market to rise due to virtual ancillary service participation; this could result in greater price convergences between the two markets.  

Under the new model, ancillary service demand curves (ASDCs) replace operating reserve demand curves (ORDCs), which adjust energy prices incrementally to align with market scarcity and provide resources with reserve payments for dispatchable supply. ASDCs, while still price-responsive, reflect the amount of ancillary service capacity available and are integrated directly into the real-time co-optimization process.  

“Participants will also be able to submit offers for ancillary services into the real-time market for the first time,” Gilman explained, noting that the new demand and offer curves will create what she called a “true” real-time market for ancillary services, as they will make it easier for the ISO to distinguish between different ancillary service products and prioritize dispatch accordingly during tight conditions.  

Regarding batteries, RTC+B is expected to streamline their market participation and boost visibility. The program labels energy storage resources as flexible assets that can pull and push electricity from the grid rather than as either generators or loads, not both. Battery owners were previously required to hold and maintain two separate datasets (one for each profile) for every resource. Since batteries will be recognized as a single resource, Gilman noted, they’ll become more “established as a unique resource type.” 

While market participation might be streamlined, the new rules could still be tricky for storage owners to navigate. Data submission is more critical than before, particularly for state of charge and ancillary service deployment factors. Gilman noted that market participants with batteries in their portfolio may also want to pay attention to the rules surrounding the Constraint Competitiveness Test (CCT), which measures the potential exercise of market power when re-dispatching the system to resolve a transmission constraint. 

“Under RTC+B, both the injection and withdrawal side of the battery will be included in the portfolio test,” she said. Still, she added that the market operator did experience difficulties actually implementing the rule changes before last week’s go-live date.  

“Participants can expect the changes to take effect in early 2026,” Gilman said.