Ancillary Services have historically been the largest source of revenue for battery energy storage systems in ERCOT - but this has changed.
As market saturation and price compression reshape the revenue landscape, the question for operators isn’t just how much they can earn from AS, but when and how it still makes sense to participate.
This report offers clear, evidence-backed guidance on how to adapt. It reveals where the best opportunities now lie - and how bidding behavior, offer strategy, and market conditions can be the difference between higher and lower revenues.
Subscribers will also be able to download the data behind this report - find the link at the bottom of the article.
Read Modo Energy’s previous analysis on Ancillary Service saturation in ERCOT here.
Executive Summary:
- Average volume offered by batteries increased by nearly 3x in ERCOT’s Ancillary Service markets in 2024, resulting in consistently lower clearing prices.
- Opportunities still exist in Ancillary Service markets, under specific scarcity conditions and narrow intervals of the day.
- Batteries that offered volume at or near market clearing prices - rather than defaulting to near-zero bids - tended to earn higher revenues.
- Revenue is increasingly concentrated in a handful of high-value days. Success now depends on precise, dynamic management of Energy and AS exposure.
- Real-Time Co-Optimization, launching in December 2025, will intensify competition - but also open new strategic options for fast-responding assets.
The key takeaways (upfront):