13 Jun 2024
Brandt Vermillion

ERCOT’s Interconnection Queue: How quickly do batteries progress?

According to the May 2024 Generation Interconnection Status (GIS) report, more than 149 GW of battery energy storage is in the ERCOT Interconnection queue. This number has been growing rapidly, up from 103 GW just twelve months ago - a 45% increase in just one year.

Every battery project in the queue that currently has a projected Commercial Operations Date (133 GW) is due online by the end of 2030.

To be clear, many of these projects will never make it to commercial operations.

For the ones that do, they’re unlikely to make it online as fast as currently projected.

So, how often do battery energy storage projects successfully complete development in ERCOT? And how long does it generally take to complete the development and commissioning processes?

Brandt outlines the interconnection timeline for commercially operational batteries in ERCOT.

The GIS report tracks the development progress of planned generation resources in ERCOT

ERCOT publishes the GIS report on a monthly basis, with historical reports dating back to the beginning of 2019.

It provides information on the number of different projects of all generation technology types currently in the development process in ERCOT.

ERCOT begins to publish project details - such as its name, location, rated power in MW, and progress updates - once a project has either:

  • started a Full Interconnection Study (FIS), or
  • signed an Interconnection Agreement (IA).

Before January 2022, ERCOT did not publish the details of ‘small’ generation projects - i.e. systems with a rated power of less than 10 MW.

For battery energy storage systems, developers often connect these projects to the distribution system rather than the transmission system.

‘Small’ generation projects require a less stringent planning study process to progress to commercial operations. As such, they have a higher rate and speed of success than projects larger than 10 MW.

How often do battery energy storage projects successfully complete development in ERCOT?

As of the beginning of June, 173 battery energy storage projects (larger than 9.9 MW) had both entered and exited the queue - with their entire development progress being visible in the GIS report.

Of these 173 projects:

  • 132 did not reach commercial operations.
  • Of those, 122 failed to either complete a Full Interconnection Study or sign an Interconnection Agreement before exiting the queue.
  • At the time they exited the queue, 102 of these projects had completed a Screening Study and started a Full Interconnection Study - but had yet to sign an Interconnection Agreement.

However, of the remaining 51 projects that progressed to that point, 41 ultimately reached commercial operations.

How long has it taken successful battery energy storage projects to become commercially operational?

Let’s look at batteries that are 10 MW or larger which have successfully become commercially operational.

From first appearing in the GIS report - either when a Full Interconnection Study was started or an Interconnection Agreement was signed - projects took a median of 1,004 days (just under 3 years) to become commercially operational.

40 of the 41 completed battery energy storage projects reached commercial operations in around 4 years or less.

And 7 of the 41 managed to reach commercial operations in under 2 years.

How long does development take following other key milestones?

Historically, completing a Full Interconnection Study or signing an Interconnection Agreement are significant milestones when assessing the likelihood of success for battery energy storage systems in development.

For projects that completed a FIS, the median time to commercial operations was 521 days. This was a relatively consistent timeline, with all successful projects coming online in .

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