Wholesale Energy

The vast majority of the power market consists of sales of wholesale energy, which is a growing share of battery revenue. In ERCOT, there are two markets for buying and selling electricity:

  • The Day-Ahead Market, where market participants contract to deliver/receive power the following day. From 10:00 am to 1:30 pm, participants submit bids and offers for energy in each of the 24 hours of the following day. ERCOT clears this market using an optimization process similar to SCED.
  • Real-Time Dispatch, in which power prices are calculated every 5 minutes by ERCOT's SCED process, and participants are paid or charged based on their real-time positive or negative balance of energy, net of energy they contracted for in the Day-Ahead Market.

Modo's ERCOT Index provides fleet-wide and asset-specific battery revenue earned in both markets.

Our Data

To calculate wholesale energy revenues, we combine the following data:

  • Real-Time Settlement Metered Net Energy - the amount of energy that each generation resource exported in real-time, in 5-minute intervals.
  • Real-Time Load Resource Data - the amount of load consumed by each load resource, in 15-minute intervals. This is necessary in addition to the Real-Time metered exports because batteries act as both generators and loads.
  • Real-Time Settlement Point Prices - the clearing price of energy at each settlement point in the ERCOT system, in 5-minute intervals.
  • Day-Ahead Generation Resource Data - the details of all offers submitted by generation resources in the Day-Ahead Market, whether they were awarded by ERCOT, and if they were, the awarded price and quantity of power to be supplied.
  • Day-Ahead Bid Awards - bids by load resources that have been accepted by ERCOT in the Day-Ahead Market. This is necessary in addition to the Day-Ahead offers data because batteries act as both generators and loads.

ERCOT supplies this data to Modo, as Modo is a registered IMRE. Modo makes this data available for all assets, not just batteries, on our API.

Additionally, Modo maintains a directory of battery assets on ERCOT, which we use to match assets to their settlement point.


After loading in all of our data, we need to connect it all together for each resource. This is challenging because each battery has multiple resource IDs used for various purposes. Additionally, some datasets aren't connected to a resource, requiring manual research to map resources to their QSE and Settlement Point. Modo's analysts maintain a database of every battery in ERCOT for this purpose.

Once each resource is joined with its market data, we have each battery's Day-Ahead positions and Real-Time operations. Now we're ready to calculate each battery's trading revenue from Day-Ahead and Real-Time:

  • Day-Ahead Energy trading - Revenues from Day-Ahead positions are calculated as the product of Day-Ahead net volume (generation minus load) multiplied by the Settlement Point price for the resource. Please note that:
    • If a QSE has multiple resources at a node, we won't know how much of the Day-Ahead contracted energy went to which resource. Therefore we assume that the contracted energy is consumed by each resource in proportion to its percent of the total rated power at the node.
  • Real-Time Energy trading - Just like in the Day-Ahead market, revenues are calculated as the product of prices and volumes. Please note that:
    • The battery's net physical operation at Real-Time is calculated as the difference between Settlement Metered Net Energy generation and its Telemetered Net Output from the Load Resource Data.
      • There are two datasets providing a generation resource's physical output - Settlement Metered Net Energy and and Telemetered Net Output from the SCED Resource Data - and one dataset providing a load resource's physical load. Settlement Metered Net Energy is the resource's power output as read by the meter and used for settlement with ERCOT. Telemetered Net Output in the SCED resource data is the value telemetered by the resource to ERCOT. For the generation side of batteries, we choose to use the Settlement Metered Net Energy dataset in our calculations because it is what is actually used in settlement.
    • Volume in Real-Time is calculated as the difference between the asset's net physical operation (as described above) and its Day-Ahead position. This is also known as the Real-Time power imbalance, which is used by ERCOT in settlement.
  • The prices used to calculate real-time prices are settlement point prices: locational marginal prices (LMPs) plus price adders. In the index breakdown, you can see the proportion of real-time revenues that come from ORDC.