San Antonio, May 20, 2026, 04:30 (CDT)
OCI Energy and CPS Energy have started construction on a 120-megawatt battery storage project in southeastern Bexar County, moving a long-planned grid resource into the build phase as San Antonio’s public utility deals with longer outages and rising power demand. The Alamo City Battery Energy Storage System, or BESS, is meant to charge when power is available and discharge when electricity demand is high.
The timing is the point. CPS Energy’s own board materials show average customer outage duration rose to 75.38 minutes in calendar 2025, missing a 64.15-minute target, while more frequent storms, equipment failures and safety-related circuit shutdowns hurt performance.
The battery will not stop a tree from falling on a line. But it gives CPS a dispatchable tool — power the utility can call on when needed — during peak demand hours, when air conditioning load and grid stress tend to rise together.
The project is rated at 120 MW of output and 480 megawatt-hours of storage, meaning it can discharge at full power for about four hours. The companies say that is enough to serve roughly 30,000 homes for up to four hours, with commercial operation expected in 2027.
OCI Energy developed and financed the project and will retain ownership under a long-term storage capacity agreement with CPS Energy, which will have operational control of the facility for the San Antonio region. ING is providing construction financing, LG Energy Solution Vertech is supplying the battery technology and Elgin Power Solutions is the engineering, procurement and construction contractor.
Sabah Bayatli, president of OCI Energy, said the project would help the electric system “better manage peak demand events.” CPS Energy Chief Executive Rudy D. Garza said storage gives the utility “flexibility to meet growing demand.” PR Newswire
Other executives framed the project as part of the same reliability push. Sven Wellock, ING’s head of renewables and power for the Americas, called the project “real, resilient infrastructure,” while LG Energy Solution Vertech CEO Jaehong Park said it would help “ease demand constraints.” PR Newswire
For OCI Holdings, the Korea-based parent, the San Antonio project is also a business-model test. BusinessKorea reported that OCI Energy is the company’s North American renewable energy unit and that OCI Holdings aims to hold more equity in projects and increase direct operations, rather than relying mainly on selling projects before completion.
The CPS storage push already includes rivals and partners beyond OCI. The utility said in 2024 it signed storage capacity agreements with Eolian for 350 MW, adding to an earlier 50 MW deal, and this month it also broke ground with Ashtrom Renewable Energy on the El Patrimonio solar project in Bexar County.
Texas is moving fast in the same direction. The U.S. Energy Information Administration forecast that utility-scale solar generation in ERCOT, the grid serving most of Texas, will overtake coal in 2026, with solar at 78 billion kilowatt-hours against 60 billion for coal. More solar raises the value of batteries that can shift power from sunny hours into evening demand.
Battery buildout has become a Texas-wide race. A Texas Solar + Storage Association presentation to ERCOT in February said installed and operating battery capacity had reached 15,712 MW, with more than 6,000 MW added in the prior year and batteries at times supplying 10% of Texas power.
The risk is that storage does not fix the whole outage problem. CPS materials blamed longer outage duration on 14 major storm events in 2025, up from 10 in 2024, along with failures involving conductors, underground residential cables and poles; the utility also de-energized circuits during planned and emergency work to protect workers and the public.
Elaina Ball, CPS Energy’s chief strategy officer, told board members the utility had “more storms than we forecast,” according to San Antonio Report. CPS also said it is using tree trimming, infrastructure upgrades and reliability programs to reduce weather-related impacts. San Antonio Report
That leaves Alamo City BESS as a useful but narrow answer: a new source of flexible capacity, not a full cure for local distribution failures. For customers, the first test will come when it is in service, demand is high and the next storm season starts doing what storm seasons now do.
