GridStor, a developer and operator of utility-scale battery energy storage projects, has secured $220 million in tax equity bridge, construction, and term debt financing for its 100 MW/400 MWh White Tank battery storage project in Arizona.

ING Capital, KeyBank, and Zions Capital Markets are the transaction’s financial partners. The financing will support the completion of the project’s development.

Located in Maricopa County, the White Tank facility will operate under a 20-year tolling agreement with Arizona Public Service (APS), which serves approximately 1.4 million homes and businesses. The battery storage project is expected to enter service in the first half of 2027.

“We are pleased to complete the financing of the White Tank battery energy storage project with GridStor,” said Filipe Barreto, Director at ING. “The rapid growth of renewable generation is driving increasing demand for energy storage solutions, making BESS assets an integral part of energy infrastructure and one of the primary themes in energy financing. This transaction reflects ING’s confidence in the sector and our commitment to financing energy infrastructure that enhances grid reliability and supports the transition to a lower-carbon energy future. We look forward to building on this success with GridStor.”

The financial close marks GridStor’s fourth major financing milestone over the past 12 months. In March 2026, the company secured a $120 million financing package provided by lending partners NORD/LB and Siemens Financial Services to support the Gunnar Reliability Project, a 150 MW/300 MWh battery energy storage project located in Hidalgo County, Texas.

In May 2026, GridStor acquired the 199 MW/796 MWh Birdseye battery storage project in Adams County, Colorado, which is expected to reach commercial operation by the end of 2028, with construction expected to begin as early as 2027.

According to Mercom’s recently released 1H 2026 Funding and M&A for Energy Storage report, publicly announced energy storage project funding reached a record $42.5 billion across 104 deals in 1H 2026, a 217% increase YoY from $13.4 billion across 48 deals in 1H 2025.