​Merchant battery energy storage revenues in ERCOT depend increasingly on energy arbitrage. Ancillary services markets are saturated, so owners and optimizers of batteries now compete for available spread capture at their respective nodes.

A battery’s ability to maximize the percentage of its available top-and-bottom spread opportunity at its node, or its capture rate, is the cleanest way to measure operational success while normalizing for locational and durational revenue opportunity. However, capture rate can vary substantially month-to-month and operator-to-operator, both due to execution and how price formation played out.

This article is a guided tour of six interactive dashboards that let you interrogate capture rate data at whatever scope matters to you: a single battery over a specific week, an optimizer’s full portfolio across two years, or a load zone during a specific weather event.

Every dashboard covers Real-Time and Day-Ahead capture rates from January 2023 through July 2026, with toggles for market, duration bucket, and date range.

Key takeaways

• In July 2026, ERCOT batteries captured 56.4% of their Real-Time TBX opportunity and 56.0% of their Day-Ahead TBX opportunity, across 280 batteries.
• Day-Ahead capture led Real-Time by 16 to 20 percentage points in May and June 2026, before the gap closed in July.
• Over the 12 months to July 2026, ERCOT batteries captured 55.3% of Real-Time TBX and 66.3% of Day-Ahead TBX.
• In July, two-hour batteries captured 62.7% of Real-Time TBX, against 49.7% for one-hour batteries.

​What’s inside

Six interactive dashboards track how batteries in ERCOT convert price spreads into revenue, from January 2023 through July 2026. The fleet-aggregate dashboard shows how Real-Time and Day-Ahead capture rates have moved month to month. The revenue dashboard shows how much of the available opportunity per kilowatt-month the average ERCOT battery converted, split by market.

The remaining dashboards allow for exploration of individual or specific groups of batteries in greater detail:

• The participant dashboard places each owner, optimizer, or QSE against the fleet average.
• The per-battery dashboard ranks every ERCOT battery by capture rate, alongside its realized and missed revenue.
• The load-zone dashboard shows how Houston, North, South, and West diverge during scarcity.
• The final dashboard compares each battery’s nodal spread with its load-zone hub, to show how nodal basis relates to capture.

​Capture rate is net revenue divided by TBX opportunity. TBX is the daily top-minus-bottom price spread, computed at each battery's own node and matched to its physical duration. A 2-hour battery is benchmarked against TB-2; a 1.5-hour battery against TB-1.5 in Real-Time and TB-2 in Day-Ahead. Net revenue is the battery's total realized wholesale revenue, including both Day-Ahead and Real-Time energy plus all ancillary services.

See Modo Energy's Indices and Benchmarking methodology for more.

​Ask Ko, free

​Ko is Modo Energy's AI analyst, and anyone can try it free by signing up for a Modo Energy account.

Ko calculates capture rates for individual ERCOT batteries, dividing each battery’s revenue by the top-bottom spread at its own node, and ranks the fleet on the same basis. It cites Modo Energy’s research library, so a pattern you spot in the dashboards below can become a question with a sourced answer.

Ask about one battery or a fleet-wide ranking for a given month. The prompts below are a starting point.

How much of the TBX opportunity do ERCOT batteries capture?

What the chart shows. Real-Time and Day-Ahead fleet-aggregate capture rates for ERCOT BESS, monthly by default, from January 2023 forward. Real-Time capture has exceeded Day-Ahead capture in eight months since January 2023, most recently in January 2026 and July 2026.

How it is derived. Sum of realized revenue per MW across all active batteries in each month, divided by the sum of matched-TBX per MW over the same period. Each battery counts equally, regardless of its size.

How to use it.

• Toggle between "all batteries" and specific duration buckets to see whether a shift is uniform across the fleet or concentrated in one duration.
• Use the date-range picker to isolate a specific quarter or event, then compare Real-Time and Day-Ahead lines.
• Hover any month to see the underlying revenue and TBX numbers.
• The dashed 100% line marks parity with the TBX benchmark. Points above it indicate ancillary services revenue stacking on top of the energy-arbitrage benchmark.

​Modo Energy subscribers can continue scrolling through to see data that allows:

• Fleet-wide average revenue and TBX opportunity per kilowatt-month,
• Capture rate by owner, optimizer, or operator (QSE),
• Per-battery and per-portfolio captured versus missed revenue, in both DAM and RTM,
• Capture rate by ERCOT load zone,
• Nodal basis and how it influences capture rate.

Creating a free Modo Energy account unlocks the dashboards below for new users: free accounts include three paid articles each month, and this is one of them.