RTC+B (real-time co-optimization plus batteries)
ERCOT's market redesign that prices energy and reserves together every five minutes and gives batteries a first-class state-of-charge model.
RTC+B is the largest redesign of ERCOT's wholesale market since it went nodal. Today, ERCOT buys ancillary services — the standby reserves that protect the grid — once, in the day-ahead market, and those assignments stay mostly frozen through the operating day. Real-time co-optimization changes that: every five minutes, the market will decide simultaneously how each resource's capability is best split between producing energy and holding reserves, and price both accordingly.
The 'plus batteries' part gives storage a proper seat at the table. Instead of modeling a battery awkwardly as a generator bolted to a load, the market treats it as a single resource with a state of charge, letting the optimization know how much energy it actually has and dispatching it within those limits.
Why it matters: when conditions tighten, today's design can strand reserve obligations on resources that would be more valuable producing energy. Co-optimization lets the market continuously reshuffle who provides what, which should mean scarcity is priced more accurately and reserves flow to whoever can provide them most cheaply at that moment. For battery operators, it rewrites the playbook — the market itself will make many of the energy-versus-reserves trade-offs that operators previously had to guess at, shifting the edge toward better price and SOC forecasting.
For the technical reader
Under RTC+B, SCED becomes a joint clearing of energy and all ancillary products at five-minute granularity, with ancillary demand curves defining scarcity pricing product by product; reserve prices become consistent by construction with real-time energy prices, since both emerge from one optimization sharing the same marginal units. Ancillary obligations, today fixed by day-ahead awards, become continuously re-optimizable positions settled against real-time AS prices.
The battery-specific changes: a combined Energy Storage Resource model replaces the split generation/load representation, with ERCOT-monitored state of charge as a dispatch constraint, and offers structured so the optimizer can move a battery between charging, discharging, and reserve provision within one interval's clearing. For quantitative operators, the binding question shifts from 'which market do I commit to day-ahead' to bid-curve design under joint energy-AS price uncertainty.
On the platform
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