Overview (ERCOT)

Modo's ERCOT BESS Index measures the battery fleet's revenue, for each 15 minute period.

We find the revenue of each battery and normalize by its rated power, broken down by revenue stream, and compare earnings for 1 hr & 2 hr duration batteries. We do this using our proprietary database of battery assets across ERCOT.

Markets

Our Index tracks revenue earned in the following markets:

• Real-Time Energy - revenue earned from net energy produced in Real-Time Dispatch, net of Day-Ahead obligations.
• Day-Ahead Energy - revenue earned from energy contracted for production via the Day-Ahead Market.
• Ancillary Services - revenue earned from a resource's Ancillary Service responsibilities at Real-Time.

These revenue components are presented for the whole fleet, regardless of duration, and normalized in dollars per megawatts of rated power.

Duration indices

Additionally, we make available an index of earnings (across all revenue components) by 1-hour versus 2-hour duration batteries. A 1-hour battery is a battery that can sustain a charge / discharge at its rated power for 1 hour.

We calculate duration by dividing the battery's storage capacity by its rated power and rounding to the nearest hour. We know every battery's storage capacity and rated power through research.

Revenue units

We quantify revenue as U.S. dollars per a quantity of time, normalized by the performance attributes of the assets in question. Let's break that down:

• period of time- this could be any period of time, but the most common are 15-minute settlement points, hours, days, and years. For example, if an asset made $100 in 15 minutes, we would multiply by 4 to make an hourly figure.
• normalized - if two assets follow the same dispatch schedule, but one has a greater rated power, they will have different revenue. In order to account for this, so that assets with different rated power or storage capacity can be compared apples-to-apples, we divide each asset's revenue by either its rated power or storage capacity.
• assets - the full-fleet index looks at all battery assets in ERCOT. The duration indices look at only battery assets with a given duration. And revenue metrics are available for individual assets also.

Our data

As an Independent Market Information System Registered Entity (IMRE), Modo Energy has access to detailed market operations data supplied directly from ERCOT. We make this data available, for all assets (not just batteries), on our API. ERCOT supplies this disclosure data on a 60 day delay. This means that every day when we update our benchmark, we are providing data about the operating day that occurred 60 days prior.

As of September 2024, we’ve updated our methodology for determining when an asset is considered operational. We now define operational status based on either the date of the first awarded day-ahead contract or the volume of settlement energy, following the asset’s synchronization according to ERCOT's GIS report.

Previously, operational status was determined solely by the date of the first awarded day-ahead contract. This sometimes led to assets undergoing testing during their synchronization period being included in our calculations prematurely, resulting in early revenue reporting for certain assets.

This change ensures a more accurate representation of asset performance and improves the precision of our Index calculations.