ING Capital, KeyBanc Capital Markets, Zions Capital Markets, and GridStor Announce Close of $220 Million Debt Financing Agreement

Supports completion of 100 MW battery energy storage facility in Arizona

PORTLAND, Ore.--(BUSINESS WIRE)--GridStor, a developer and operator of utility-scale battery energy storage systems, together with financial partners ING Capital LLC, KeyBank N.A., and Zions Capital Markets announced the close of a $220 million tax equity bridge, construction, and term debt financing agreement to complete the development of GridStor’s 100 MW / 400 MWh White Tank battery energy storage facility in Arizona.

The White Tank facility will be operated via a 20-year tolling agreement with Arizona Public Service (APS), the state’s largest electric utility serving approximately 1.4 million homes and businesses. The project is sited in Maricopa County and is expected to be placed in service in the first half of 2027.

“We are proud to work with three distinguished financial partners to complete the financing of the White Tank Reliability Project,” said Chris Taylor, CEO, GridStor. “Trusted partnerships like these are critical for advancing large-scale power supply and infrastructure to meet surging demand for new power capacity. We thank ING, KeyBanc Capital Markets, and Zions for placing their trust in us.”

GridStor’s construction of standalone battery energy storage in Arizona comes as the state’s utilities break all-time records for power demand, with APS notching peak electricity service on August 2 that was 5% higher than the previous record set in 2025. The White Tank battery storage project will reinforce APS’ system reliability, helping to ensure electric customers have access to power when they need it most and sustain the region’s expanding population and new industrial facilities.

“We are pleased to complete the financing of the White Tank battery energy storage project with GridStor,” said Filipe Barreto, Director, 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.”

“Battery storage has become an essential part of how utilities address growing load, reliability requirements and changing grid conditions,” said Greg Berman, Managing Director, Utilities, Power & Renewable Energy, KeyBanc Capital Markets. “We're proud to have arranged this financing for GridStor’s White Tank project and support the development of infrastructure that can be deployed quickly and at scale to help address the nation's evolving energy needs.”

“We are pleased to provide this strategic financing to support the continued growth of Arizona’s energy capacity,” said Robert Park, Head of Power and Project Finance, Zions. “This transaction underscores our Power and Project Finance team’s expertise in structuring tailored financial solutions in the power sector, and we are proud to have supported GridStor in this project transaction.”

The successful financial close of the project marks GridStor’s fourth major financing milestone within the past twelve months. Backed by Goldman Sachs Asset Management, GridStor manages a project pipeline of over 3 GW of battery storage projects in later-stage development or under construction across the western and central U.S. The company expects to continue acquisitions of advanced-stage projects that provide cost-effective, near-term solutions to utilities, data centers, and other large industrial customers in regions with rapidly growing energy demand.

About GridStor

GridStor strengthens America’s power system reliability by building and operating battery projects, storing electricity to deliver when and where it’s most needed. GridStor develops, acquires, builds and operates utility-scale, standalone battery storage projects primarily across North America. Visit us at www.gridstor.com and on LinkedIn.

About ING Capital LLC

ING Capital LLC is a financial services firm offering a full array of wholesale financial lending products and advisory services to its corporate and institutional clients. ING Capital LLC is an indirect U.S. subsidiary of ING Bank NV, part of ING Groep NV (NYSE: ING), a global financial institution with a strong European base. The purpose of ING Bank is empowering people to stay a step ahead in life and in business. ING Bank’s more than 60,000 employees offer retail and wholesale banking services to customers in over 100 countries. Please note that neither ING Groep NV nor ING Bank NV have a banking license in the U.S. and are therefore not permitted to conduct banking activities in the U.S.

About KeyCorp

KeyCorp's roots trace back more than 200 years to Albany, New York. Headquartered in Cleveland, Ohio, Key is one of the nation's largest bank-based financial services companies, with assets of approximately $191 billion at June 30, 2026.

Key provides deposit, lending, cash management, and investment services to individuals and businesses in 15 states under the name KeyBank National Association through a network of approximately 950 branches and approximately 1,100 ATMs. Key also provides a broad range of sophisticated corporate and investment banking products, such as merger and acquisition advice, public and private debt and equity, syndications and derivatives to middle market companies in selected industries throughout the United States under the KeyBanc Capital Markets trade name. For more information, visit https://www.key.com/.

About Zions Bancorporation

Zions Bancorporation, N.A. is one of the nation's premier financial services companies with approximately $89 billion of total assets at December 31, 2025, and annual net revenue of $3.4 billion in 2025. Zions operates under local management teams and distinct brands in 11 western states: Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Texas, Utah, Washington, and Wyoming. The Bank is a consistent recipient of national and state-wide customer survey awards in small- and middle-market banking, as well as a leader in public finance advisory services and Small Business Administration lending. In addition, Zions is included in the S&P MidCap 400 and NASDAQ Financial 100 indices. Investor information and links to local banking brands can be accessed at www.zionsbancorporation.com.

Zions Capital Markets is the trade name for certain business activities of Zions Bancorporation, N.A., and its divisions and subsidiaries. For more information and important disclosures please visit www.zionscapitalmarkets.com.

About Goldman Sachs Asset Management

Goldman Sachs Asset Management is the primary investing area within Goldman Sachs (NYSE: GS), delivering investment and advisory services across public and private markets for the world’s leading institutions, financial advisors and individuals.

The business is driven by a focus on partnership and shared success with its clients, seeking to deliver long-term investment performance drawing on its global network and deep expertise across industries and markets.

Goldman Sachs Asset Management is a leading investor across fixed income, liquidity, equity, alternatives and multi-asset solutions. Goldman Sachs oversees approximately $3.7 trillion in assets under supervision as of March 31, 2026.

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