Flatiron Energy Secures $850 Million Financing for 1,200 MWh Chelsea Battery Storage Project in US

Flatiron Energy has completed a financing package of roughly USD 850 million in construction and term commitments for the Energizar Project, a battery energy storage facility planned for Chelsea, Massachusetts.

The announcement, dated October 15, 2026, confirms that the capital raised will carry the 1,200 MWh asset through construction and into operation, with commercial operations targeted for the fourth quarter of 2027.

A Boston-Area Grid Asset Takes Shape Through a Multi-Layered Capital Raise

The raise was not structured as a single loan but as a layered package. It brings together construction and bridge loan facilities, term loan facilities, letter of credit facilities, a preferred equity commitment, and a tax credit transfer commitment.

Two Fortune 500 corporations have agreed to transfer a portion of the project's investment tax credits, while the preferred equity was committed by funds managed by a global credit asset manager with more than USD 350 billion in assets under management.

Banking Group Led by Nord L/B, Santander, and Societe Generale

The debt side of the transaction was arranged by a consortium of banks. Nord L/B, Santander, and Societe Generale took on the roles of Coordinating Lead Arrangers. Investec and East West Bank acted as Joint Lead Arrangers, and Siemens Financial Services joined as a Lender.

Administrative duties were split, with Santander serving as Administrative Agent and East West Bank acting as Depositary. The banks framed the deal in the context of the regional power market.

Andrew Platt, Managing Director at Santander, called the financing an important milestone for the ISO New England market and said it would contribute to a more reliable and resilient power system.

He noted that battery storage assets are playing an increasingly critical role in supporting grid stability and facilitating the integration of energy resources across the United States.

Kevin Cartoski, a Director on Societe Generale's Energy, Mining, and Industrials team, described Energizar as a unique urban battery storage project that will help meet clean energy goals in Massachusetts.

Sondra Martinez, Head of Project Finance-Origination at Nord L/B, said the closing reflects the bank's significant expertise in and continued commitment to financing battery storage projects.

What Energizar Will Deliver to the Boston Grid

Once complete, Energizar is expected to stand as the largest battery energy storage system facility on the East Coast and one of the largest urban BESS facilities in the world. The 1,200 MWh asset is designed to supply critical capacity and peaking energy resources for communities that depend on the Boston grid.

Flatiron's Chief Financial Officer, Dan Myers, said the project represents the culmination of years of work by many stakeholders.

In his view, projects of this complexity and scale only happen because of support from the local community, policy makers, equipment and EPC providers, offtakers, and financing counterparties.

Myers added that Flatiron is proud to contribute to the next phase of the region's grid reliability and capacity resources.

Advisors Behind the Transaction

A group of legal and advisory firms supported the deal from both sides of the table. Orrick, Herrington & Sutcliffe LLP and Foley Hoag LLP represented Flatiron, while Winston Taylor LLP and Rath, Young, and Pignatelli, P.C. acted for the lenders.

CCA Capital LLC advised Flatiron on the preferred equity investment and the tax credit transfer. Riverside Risk Advisors served as Hedge Advisor to Flatiron in connection with interest rate hedging activities, and Raymond James Renewable Energy Investments advised the tax credit purchasers.

The Institutions Financing the Deal

Nord/LB, formally Norddeutsche Landesbank - Girozentrale, is one of the leading German commercial banks. Its core business spans corporate customers and private and commercial customers, including private banking, special finance in the energy and infrastructure sector, and commercial real estate finance. Headquartered in Hanover, Germany, the bank maintains branches in London and New York.

Banco Santander, founded in 1857 and headquartered in Spain, ranks among the largest banks in the world by market capitalization. According to the announcement, the bank held USD 1.68 trillion in total funds in the first half of 2026, alongside more than 182 million customers, 6,500 branches, and 185,000 employees.

Societe Generale, a European bank with roughly 110,000 employees, serves 27 million clients across 58 countries. The institution has supported economic development for over 160 years, providing advisory and financial solutions to corporate, institutional, and individual clients.

A Largest-of-Its-Kind Facility for New England

With financing now closed, the Energizar Project moves toward a fourth-quarter 2027 commercial operation date, at which point it is expected to hold the distinction of being the largest BESS facility on the east coast while adding storage capacity to the Boston grid for the communities it is intended to serve.