In this US news roundup, battery energy storage system (BESS) project updates from Spearmint Energy in Texas, Polaris Renewable Energy in Puerto Rico, and Clearway Energy Group in Utah.
Spearmint Energy achieves commercial operation on two Texas BESS
Battery storage developer and operator Spearmint Energy has achieved commercial operation on two battery energy storage systems (BESS) in Texas.
Announced 12 May, the 100MW/200MWh Tierra Seca and 100MW/200MWh Seven Flags BESS projects, located in Del Rio and Laredo, respectively, began operation in late December 2025, and have completed nearly six months of operations.
Construction of the projects was led by engineering, procurement, and construction (EPC) firm Mortenson. They both use PV inverter and BESS company Sungrow’s PowerTitan 2.0 energy storage platform.
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PowerTitan 2.0 integrates a 5MWh battery with a 2.5MW power conversion system (PCS) into a standard 20-foot container. In June 2025, the company launched its PowerTitan 3.0 system, and claimed the 30-foot product as the world’s largest BESS in terms of capacity and energy density.
In April 2025, Spearmint Energy secured US$250 million for the Tierra Seca and Seven Flags BESS projects.
The US$250 million financing comprised US$59 million in construction-to-term loan facilities provided by Manulife, US$95 million in tax equity bridge loan facilities provided by East West Bank and Investec and US$98 million in tax equity commitments from Sugar Creek Capital.
In 2022, Energy-Storage.news reported that energy development group Black Mountain Energy Storage (BMES) had signed an exclusivity agreement with developer Cypress Creek Renewables for the two BESS projects, as well as two additional BESS projects.
Spearmint has not provided further details about how it acquired Tierra Seca and Seven Flags.
In January 2026, Spearmint closed an equity investment in the projects from Kyuden International, the overseas business arm of Japanese utility company Kyuden Group.
This marked Kyuden’s first excursion into US-based BESS, building on its solar and gas turbine combined cycle power plant investments.
Polaris Puerto Rico BESS receives approval
Renewables developer Polaris Renewable Energy’s BESS Standard Offer (SO1) agreement has been approved by the Financial Oversight and Management Board of Puerto Rico (FOMB).
In August 2025, Polaris, on behalf of the Puerto Rico Electric Power Authority (PREPA) submitted the SO1 to the Puerto Rico Energy Bureau (PREB).
In Puerto Rico, electric generation, transmission, and distribution facilities are managed by PREPA and privately operated by Luma Energy. Both PREPA and Luma fall under the oversight of PREB.
The SO1 agreement was intended to be executed between PREPA and Polaris Power US, Inc., a subsidiary of Polaris. It was submitted with a BESS capacity of 71.4MW, made up of 35.7MW across two projects.
In March 2026, PREPA approved the SO1, but its execution rested on the approval of the FOMB.
It forms part of the Puerto Rico Accelerated Storage Addition Programme (ASAP), which seeks to improve grid reliability throughout the island by adding utility-scale BESS alongside existing power generation facilities.
Polaris’ SO1 also follows the failure of multiple IPPs to execute BESS projects through the ASAP framework.
PREPA and Polaris will be responsible for the installation and operation of the BESS, while Punta Lima Wind Farm, another subsidiary of Polaris, will continue to serve as the “Generation Facility Owner” for the Punta Lima site where the storage system will be located.
Once the BESS project is constructed and fully operational, PREPA and Polaris will be entitled to receive monthly fixed and performance-based payments from PREPA in exchange for providing energy storage services, including capacity and grid support.
The Storage Capability Payment Price (SCPP) applicable to each billing period is US$16,000-per-MW-per-month of tested storage capability, with no price escalation during the term.
The SCPP would increase to US$20,600-per-MW-per-month if PREPA and Polaris do not qualify for eligible investment tax credits (ITCs).
However, pursuant to conditions included in the FOMB approval, the lower SCPP of US$16,000-per-MW-per-month would continue to apply if ITC eligibility is not achieved due to foreign entity of concern (FEOC)-related sourcing or procurement decisions. The term of the SO1 Agreement is 20-years from the commercial operation date (COD).
Polaris claims it is actively advancing its procurement and sourcing strategy with the objective of achieving compliance with applicable FEOC requirements and preserving ITC eligibility for the project. It expects to provide updated estimates for capital expenditure and COD timing within approximately one month.
Last month in Puerto Rico, PREB approved a motion from Tesla, residential solar and battery installer Sunrun, and residential solar installer SunStrong Management to auto-enroll participants in the Customer Battery Energy Sharing (CBES) programme, created by the Governing Board of PREPA.
Clearway Energy brings online 1,280MWh Honeycomb Energy Centre in Utah
IPP Clearway Energy Group has brought online its 320MW/1,280MWh Honeycomb Energy Centre, in Utah.
A ribbon cutting event was held to mark the occasion on 6 May, featuring Senator John Curtis. Clearway also donated US$150,000 to a local nonprofit working to provide stable housing to individuals transitioning out of homelessness.
Clearway claims the project represents an approximately US$600 million investment in Utah’s electric infrastructure, with equipment from Tesla and domestic steel.
In March 2025, Clearway closed a US$605 million financing for the Honeycomb portfolio, led by a consortium consisting of KeyBanc Capital Markets, CoBank ACB, DNB Bank ASA, New York Branch, US Bancorp Impact Finance), National Australia Bank Limited, Bank of America, National Association and Norddeutsche Landesbank Girozentrale, New York Branch.
Honeycomb Energy Center includes four distinct 80MW BESS, contracted under 20-year agreemets with Berkshire Hathaway Energy-owned utility PacifiCorp.
Clearway also said each of the BESS are constructed adjacent to Clearway owned and operated solar projects.
The company claims that Honeycomb will generate US$60 million in propery and sales taxes for schools and public services, created 150 jobs at peak construction, sustain more than 12 full-time positions, and support local landowners with “long-term leases that help preserve their land and legacy.”
In February, Clearway brought online the 300MW solar PV and 200MW BESS Pine Forest Energy Centre in Hopkins County, Texas.
Pine Forest is supported by long-term virtual power purchase agreements with Dell Technologies and Universal Corporation. In 2024, Clearway committed to investing in the project once it became commercially operational.
