California-headquartered developer esVolta has acquired a 150MW/300MWh standalone BESS in Texas, US, from Black Mountain Energy Storage (BMES).
A source close to the matter confirmed to Energy-Storage.news that a sale of a project had taken place, revealing that the sale formed part of a wider portfolio transaction made up of three BESS projects located in the Electric Reliability Council of Texas (ERCOT) region.
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Founded in 2021, BMES has a track record of selling standalone BESS projects across the US after completing early development work. As reported by Energy-Storage.news at the beginning of this year, BMES sold an 800MWh BESS located in Oklahoma to Goldman Sachs-backed developer GridStor.
Energy-Storage.news has also reported on previous BMES Texas project transactions with Vitis Energy, UBS Asset Management and Recurrent Energy.
BMES filed interconnection request for Bufflehead project in 2022
The project in question, known as Bufflehead BESS, was first introduced into the public domain in February 2022, when BMES filed an interconnection request with ERCOT for the development.
This was followed up in 2023 when the developer submitted zoning change and site plan applications with Collin County’s City of Wylie, approved in July and August respectively.
At the time, BMES was proposing a 200MW/400MWh lithium-ion standalone BESS on 9 acres of land connecting to the grid via Oncor Electric Delivery’s Lavon 138kV switching station at an approximate cost of US$180 million.
By securing an ERCOT interconnection agreement in September 2024, coupled with receiving approval from the City of Wylie, BMES cleared several key development milestones for Bufflehead.
esVolta brought into project development
Shortly after securing an interconnection agreement, BMES went back to the City of Wylie during October 2024 to amend its previously approved site plan.
According to the amended site plan, BMES requested the change to Bufflehead after partnering with esVolta on development of the project to install “more advanced battery energy storage systems.”
The new site layout submitted with the City of Wylie allows for a smaller 150MW/300MWh of battery storage capacity.
Although battery technology wasn’t specified within BMES’ initial plan, the amended application proposed that Bufflehead could utilise Sungrow’s PowerTitan 2.0 lithium iron phosphate (LFP) energy storage system.
According to Sungrow, its next generation PowerTitan BESS product includes robust fire safety features that exceed requirements outlined by National Fire Protection Agency (NFPA) standards.
As reported by Energy-Storage.news, in a self-proclaimed world-first event at this scale, Sungrow conducted large-scale fire testing (LSFT) of its PowerTitan 2.0 unit during November 2024.
esVolta acquisition of Bufflehead BESS
On 13 March 2025, an amended interconnection agreement for Bufflehead was filed with the Public Utilities Commission of Texas (PUCT), which assigned a new business subsidiary to the project – Boxcar Energy Storage, LLC.
Unlike the initial agreement, which a BMES employee signed, the amended interconnection agreement included the signature of esVolta’s Vice President of Development, Conor Goodson.
After reaching out for comment, a source at esVolta confirmed to Energy-Storage.news that it had recently acquired the project. According to ERCOT’s most recent interconnection queue, Bufflehead BESS will come online in July next year.
Sources at both BMES and esVolta were unable to comment further on the sale of the three projects.
BMES energy storage developments in ERCOT
BMES holds several ERCOT queue positions for standalone BESS projects at various stages of development across Texas.
The developer has secured interconnection agreements for three of these projects:
- Goldeneye BESS (25INR0100) – 200MW of storage capacity in Bell County.
- Soho II BESS (25INR0162) – 200MW of storage capacity in Brazoria County.
- Great Rock BESS (25INR0230) – 300MW of storage capacity in Leon County.
Since its 2021 inception, BMES claims to have sold 20 projects in the ERCOT region, representing 3GW of cumulative battery storage capacity.
It also claims to have a further 1.6GW of BESS developments as part of its ERCOT pipeline comprising 11 projects.
esVolta transacts with Captona for three Texas storage projects
esVolta was acquired by infrastructure investment firm Generate Capital in 2022 and has since built its development portfolio to a claimed 30 projects with a cumulative storage capacity exceeding 24GWh across the US.
As reported by Energy-Storage.news, the developer made headlines in late January after it completed a preferred equity transaction with Captona for three Texas BESS projects in a US$243 million deal including the transfer of tax credits.
The three projects, referred to as Anole, Desert Willow and Burksol, are all expected online by the year end.
