What happened on December 5, 2025?

On December 5, 2025, ERCOT successfully launched Real-Time Co-optimization Plus Batteries (RTC+B), the most significant upgrade to the ERCOT real-time nodal market since 2010. This change modernizes how ERCOT dispatches electricity and procures Ancillary Services, and it improves how Battery Energy Storage Resources are represented in real time.

ERCOT’s market notice and program updates are available on the ERCOT site:
https://www.ercot.com/services/comm/mkt_notices/M-F110525-01

What is RTC+B, in plain English?

Before RTC+B, ERCOT’s real-time market optimized energy dispatch first, and then handled Ancillary Services separately. That meant the system sometimes had to “re-fix” reliability needs after energy was already scheduled.

RTC+B solves that by co-optimizing both energy and Ancillary Services at the same time, every real-time dispatch interval. ERCOT can now pick the lowest-cost mix of electricity and reliability services together, instead of making two disconnected decisions.

ERCOT’s RTC+B overview and background:
https://www.ercot.com/files/docs/2024/09/13/ERCOT-Trending-Topic-RTC-B.pdf

Why batteries are at the center of this upgrade

Texas has added batteries rapidly in recent years, often paired with solar. Batteries help the ERCOT grid by:

• absorbing excess solar and wind when supply is high
• injecting electricity instantly during peak demand
• providing fast, flexible reliability services when the grid is stressed

RTC+B finally gives ERCOT a dispatch and pricing engine that treats batteries like the flexible grid tools they are, not like old-school generators with a different paint job.

Battery modeling details from ERCOT:
https://www.ercot.com/files/docs/2024/09/13/ERCOT-Trending-Topic-RTC-B.pdf

Operational and reliability benefits ERCOT expects

ERCOT has outlined several practical gains from RTC+B:

1. More timely procurement and management of Ancillary Services for real-time grid stability.
2. Better congestion management by using a wider variety of resources, including batteries.
3. Fewer manual operator actions because the market engine handles more reliability needs automatically.
4. Single-device battery modeling so ERCOT can dispatch stored energy based on true state of charge.
5. Replacement of inefficient supplemental reserve constructs with real-time co-optimization.

ERCOT estimates these changes will drive major wholesale efficiency benefits, with projected savings exceeding one billion dollars annually.

Ancillary Services background from ERCOT:
https://www.ercot.com/files/docs/2024/10/07/ERCOT-Ancillary-Services-Trending-Topic.pdf

How we got here: PUCT oversight and stakeholder work

The Real-Time Co-optimization effort began in 2019 after direction from the Public Utility Commission of Texas to evaluate real-time co-optimization in ERCOT. As batteries became a major resource category, the effort expanded into RTC+B.

Implementation was coordinated through the Real-Time Co-optimization plus Batteries Task Force under ERCOT’s Technical Advisory Committee. ERCOT and market participants completed testing, market trials, and training leading up to go-live.

ERCOT RTC+B Task Force and training materials:
https://www.ercot.com/committees/tac/rtcbtf/training

ERCOT Board update on RTC+B progress:
https://www.ercot.com/files/docs/2025/09/16/8.5-Board-RTCB-Update-REVISED.pdf

What RTC+B means for solar, renewables, and the Texas electricity market

RTC+B is not just a battery rule. It is a grid resiliency upgrade for a system increasingly powered by renewables.

• Solar and wind variability increases real-time balancing needs.
• Batteries, paired with RTC+B, reduce balancing costs by reacting instantly to system conditions.
• Improved real-time price signals support smarter investment in storage and renewable projects.

Bottom line: a cleaner resource mix becomes easier to operate reliably, and that helps Texas keep adding renewables without sacrificing grid stability.

The consumer angle: why Texans should care

Most Texans do not follow dispatch algorithms daily. Here is the practical takeaway:

RTC+B is designed to lower inefficiency costs in the wholesale market and improve reliability during tight conditions. Over time, that tends to show up as:

• fewer scarcity events driven by avoidable market friction
• better use of batteries to cover peaks
• downward pressure on wholesale prices, especially during high-renewable hours

Retail prices will not drop overnight. But more efficient real-time markets are one of the core levers that keep long-run electricity costs in check in a fast-growing state.

Gatby’s view

Gatby is an electricity marketplace. We win when the Texas grid is reliable, competitive, and increasingly powered by renewables. RTC+B supports all three.

By letting batteries and other flexible resources compete and perform properly in the real-time market, ERCOT is upgrading the operating system of the Texas grid. That enables more solar, more storage, and stronger resiliency. And the more efficient the wholesale market becomes, the better the options Texans can access when shopping for power.

Power move: grid upgrades are boring until they save you money during a heat wave. RTC+B is one of those upgrades.

FAQ: RTC+B, Batteries, and the Texas Grid

What does RTC+B stand for?
RTC+B stands for Real-Time Co-optimization Plus Batteries. It is ERCOT’s new real-time market design that co-optimizes energy and Ancillary Services together, while also modeling Battery Energy Storage Resources with state-of-charge awareness.

Why did ERCOT need RTC+B?
Texas’s resource mix has changed fast, especially with growth in solar, wind, and batteries. RTC+B updates the real-time market so ERCOT can dispatch electricity and reliability services more efficiently in a grid dominated by flexible, renewable-driven resources.

How do batteries improve ERCOT grid reliability?
Batteries can respond almost instantly. They charge when electricity is abundant and cheap, then discharge during peak demand or emergencies. They also provide fast reliability services that help stabilize frequency and manage sudden changes in solar or wind output.

Does RTC+B help solar and renewables?
Yes. Solar and wind can change quickly with weather. RTC+B helps ERCOT balance the grid in real time by letting batteries and other flexible resources compete to cover those swings. That makes it easier to add more renewables without sacrificing reliability.

What are Ancillary Services, and why are they important?
Ancillary Services are reliability tools ERCOT buys to keep the grid stable. They include reserves and rapid-response services used to manage outages, forecast errors, or unexpected changes in demand or renewable output. ERCOT’s background is here:
https://www.ercot.com/files/docs/2024/10/07/ERCOT-Ancillary-Services-Trending-Topic.pdf

How does co-optimization lower electricity costs?
When energy and reliability services are optimized together, ERCOT can avoid inefficient commitments and reduce manual interventions. That cuts waste in the wholesale market. Over time, lower wholesale costs reduce upward pressure on retail electricity prices.

Will Texans see lower power bills right away?
Not instantly. Retail prices depend on many factors. But RTC+B reduces wholesale inefficiencies and improves reliability during tight conditions, which helps keep long-run electricity costs lower than they otherwise would be.

Where can I read ERCOT’s official RTC+B materials?
Start with ERCOT’s RTC+B overview:
https://www.ercot.com/files/docs/2024/09/13/ERCOT-Trending-Topic-RTC-B.pdf
You can also see task force updates and training here:
https://www.ercot.com/committees/tac/rtcbtf/training

Does RTC+B change how retail customers choose an electricity plan?
Indirectly. RTC+B is a wholesale market upgrade. But by improving grid resiliency and efficiency, it strengthens the market conditions that competitive retail pricing depends on. It is a behind-the-scenes change with real front-of-house benefits over time.