Everything is bigger in Texas, and the ERCOT power stack keeps proving the saying. Load has been climbing for years — structural growth tied to data centers and electrification now dominates every forward conversation — and the supply side has been racing to keep up. Solar led the last wave, swelling into a midday force big enough to bend the price curve and carve a hole in the daytime thermal call. Now it is batteries making their move, scaling fast enough to swing thousands of megawatts between a midday charge trough and an evening discharge peak. A fleet that barely registered two years ago has become a daily player in its own right.

Figure 1 | ERCOT Three-Year 12x24 Profiles – Power Storage, Coal, and Natural Gas

That growth is doing more than reshaping battery revenue — it is starting to rewrite the coal and gas profiles around it, and not always in the direction you would expect. In our latest special report, Batteries Getting Bigger in Texas, we line up the three-year 12x24 profiles for storage, coal, and gas and find that the fleet's charging and discharging hours push the thermal stack in surprisingly different directions. This is illustrated in the figure above. The upshot is that the shape of the daily coal and gas curves is increasingly being written by when the batteries choose to charge and discharge, not just by where the weather leaves net load. During maximum charge hours for batteries, we even see a year-over-year increase in thermal activity (for both coal and natural gas) turn positive in June as charging hours are propping up thermal demand.

Figure 2 | ERCOT Net Load, 7-Day Moving Average

Why does the timing matter so much right now? Because the next week sets up as a live test. The past stretch has been quiet, with abundant wind and mild conditions holding prices down and leaving little for batteries to work with. That is about to change. As the Daily Summary dashboard shows, wind is forecast to roll off hard — from the mid-20s GW last weekend toward single digits by around July 6 — even as heat builds and peak load holds firm near 80-plus GW. The result is a net-load profile that climbs roughly 8 to 9 GW from today into the weekend, pushing toward the mid-40s GW.

A rising net-load ramp with wind stepping aside is exactly the environment where the growing battery fleet earns its keep, leaning into the evening peak as the cheap midday energy it stored gets redeployed. It is also the setup that makes the report's analysis timely: the bigger the fleet gets, the more the daily thermal profile bends around it — and the more those charge-and-discharge decisions shape the hours that matter most.

For the full breakdown of how the ERCOT storage buildout is reshaping the coal and gas stack, read our latest special report, Batteries Getting Bigger in Texas, part of the Energy GPS Professional Subscription. Reach out at [email protected] for more.