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Blackstone portfolio company Aypa Power has closed an US$88 million construction and term loan facility for Wolf Tank, a 173MWh standalone energy storage project in Texas.

Energy storage and hybrid asset developer, owner and operator Aypa has closed the debt deal with CIT, a division of First Citizens Bank, and Siemens Financial Services.

Wolf Tank is a 173MWh standalone battery energy storage system (BESS) project in Webb County, Texas. It will begin commercial operations in 2023 and support the delivery of dependable electricity supply in the south region of the grid operator, Electric Reliability Council of Texas (ERCOT).

“As energy demands continue to grow in Texas, so do challenges with reliability,” said Aypa Power CEO, Moe Hajabed. “Wolf Tank and other Aypa energy storage and hybrid projects within our 12GW pipeline will provide flexible capacity to better meet peak load needs.”

A press release did not reveal the hours’ duration or MW of the project. But a filing with the Public Utility Comission of Texas dated 2 June, 2022, said that the Wolf Tank project would be a one-hour system with a power and capacity rating of 150MW/150MWh.

Assuming the Filing is still accurate as regards duration, the one-hour rating is noteworthy as many (if not most) projects are moving to two-hour durations as the ERCOT market increasingly moves to wholesale energy trading as a proportion of BESS revenues.

This now stands at around half of revenues according to investor Gore Street Capital which recently entered the market, with the remainder mainly from ancillary services, primarily regulation reserve service (RRS) and a sub-set of that called fast frequency response (RRS-FFR).

Just in the past month, projects brought online by Jupiter Power, acquired by Canadian Solar subsidiary Recurrent Energy, and funded by US development bank NADBank have all been two-hour systems. Having said that, none are as large in MW as Wolf Tank’s (again assuming one hour) and a recent 260MW project brought online by Vistra – the state’s largest – was also a one-hour system.

Blackstone, one of the largest private equity firms in the world, acquired Aypa Power in 2020 when it was a commercial & industrial-focused (C&I) storage provider called NRSTOR C&I, before re-branding it a few months later.