In August, three new battery energy storage systems became commercially operational in ERCOT. Together, they bring the total installed energy capacity to around 9 GWh. Total installed rated power is now just under 6 GW.
Each system is a two-hour duration battery with a rated power of more than 100 MW.
The three new battery energy storage systems are also located across the state:
- Tesla’s 131 MW Giga Texas Energy Storage is on-site at their Gigafactory, right outside Austin.
- Aypa Power’s new Borden County BESS is a 150 MW system located in West Texas.
- Jupiter Power’s Callisto One Energy Center is a 206 MW battery built on the site of a former gas-fired power plant in Southwest Houston.
Historically, the buildout of battery energy storage systems has been most pronounced in West Texas. However, in 2024, this has begun to change.
How is battery energy storage buildout in ERCOT evolving?
At the beginning of 2024, batteries in the West Load Zone made up 43% of installed rated power.
However, through the end of August, this has fallen to 35% of total installed rated power.
Thus far in 2024, the South Load Zone has seen the largest growth in both the number and magnitude of installed battery energy storage systems.
In fact, nine new batteries have become commercially operational in the South Load Zone in 2024. This has increased capacity in the region by 874 MW and 1,453 MWh.
The commencement of commercial operations of Jupiter Power’s Callisto I Energy Center also marks an important milestone. Callisto is the first ever battery with a rated power larger than 100 MW to become commercially operational in Houston.
Prior to August, the Houston Load Zone had just 459 MW and 676 MWh of total installed battery energy storage capacity.
The site can also reportedly accommodate an additional 400 MW and 800 MWh of battery energy storage projects.
Ultimately, as time goes on, the location of battery energy storage systems in ERCOT is becoming more diversified.
Does the anticipated BESS buildout through the end of 2025 mirror this trend?
Callisto One is the first battery energy storage system larger than 100 MW to be built in Houston. However, this is just a sign of things to come.
By the end of next year, the Houston Load Zone is projected to have more than 4 GW of battery energy storage projects become commercially operational.
Additionally, buildout in August kept pace with Modo’s projection. This means we’re still expecting total installed rated power to be between 14 and 18 GW by the end of 2025.
The majority of projects with projected commissioning dates in December of 2025 have signed interconnection agreements. However, they have yet to progress any further in the commissioning process.
This means that several steps - such as inclusion in a Quarterly Stability Assessment - still need to be completed before approval for energization, synchronization, and full commercial operations.
Modo uses the median time to interconnect from each project’s current stage in the process, as outlined in our previous buildout update. In reality, sites that are earlier in the process have a wider range of potential commissioning dates.
As a result, some projects will be commissioned earlier in the year than projected. Conversely, others won't become commercially operational until some time in 2026.
Ultimately, this results in a high degree of confidence that buildout will have reached at least 14 GW by the end of next year.
Modo subscribers can download the dataset behind the charts using the link below.