Platts launches new US Battery Energy Storage System Arbitrage Indexes

Platts, part of S&P Global Energy, has launched the North American Battery Energy Storage Systems (BESS) Arbitrage Indices for the US market, effective June 1, 2026.

BESS stores energy from sources like solar, wind, or the grid for later use. The use of batteries has grown in the US energy mix, especially in the California Independent System Operator and the Electric Reliability Council of Texas, as market participants rely more on solar and storage to meet rising demand.

The BESS Arbitrage Indices summarize potential daily arbitrage opportunities by identifying the top-priced and bottom-priced hours using hourly price averages from CAISO and ERCOT data. Platts publishes arbitrage indices for the Top-Bottom 4 (TB4) and Top-Bottom 2 (TB2) hourly windows to demonstrate when charging and discharging could be most profitable. Platts publishes TB4 for both CAISO and ERCOT, and TB2 for ERCOT.

These daily assessments will be published based on the previous day's pricing data from ERCOT and CAISO, providing insight into recent price fluctuations. For TB4, the index averages the four highest and lowest hourly prices across both ISOs and calculates the spread between them to indicate arbitrage potential. The TB2 indices follow a similar process for the two highest and lowest hourly prices. Platts will also publish corresponding monthly averages for each index.

The newly launched symbols are as follows:

These indexes are published daily in Megawatt Daily, Energy Trader, and Alert Pages AGP0008, PEA0018, AGP0009, and PEA0019.

Please send all feedback, comments and questions to powerpricing@spglobal.com or pricegroup@spglobal.com .

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