Flatiron Energy, a rapidly growing independent power producer (IPP) focused on battery energy storage, announced a significant expansion of its financial backing with the closing of an upsized $250 million corporate credit facility, funded by funds managed by HPS Investment Partners (HPS). The new financing doubles the company’s prior $125 million facility established in 2024. And it will fund the development and construction of Flatiron’s 4.5 GW / 18 GWh portfolio of utility-scale battery energy storage assets across the United States.
In addition to the expanded credit facility, Flatiron’s existing equity partner, Hull Street Energy (HSE), has increased its equity commitment, positioning the company to strengthen its foothold as a leading regional IPP in the Northeast and Mid-Atlantic power markets. These capital commitments arrive shortly after Flatiron closed $540 million in project financing for its Taft Project in Uxbridge, Massachusetts, a flagship battery energy storage facility supporting regional grid stability and decarbonization.
The combined financial resources will allow Flatiron to advance several shovel-ready projects in New England while expanding its development pipeline in other U.S. regions facing growing demand for grid-scale storage. The company’s focus remains on delivering reliable, flexible, and clean power capacity to offset variability in renewable generation as states and utilities transition toward net-zero targets.
Flatiron’s growth strategy emphasizes first-mover advantage in key ISO and RTO markets such as ISO-New England (ISO-NE) and New York ISO (NYISO)—regions characterized by both aging fossil generation and increasing renewable integration. The company’s growing portfolio of operational and development-stage assets provides critical “firming” capacity that supports grid reliability and enables more consistent renewable power delivery.
HPS, a global leader in infrastructure credit and part of BlackRock Private Financing Solutions, brings deep expertise in structuring and scaling capital for energy transition assets. Meanwhile, HSE’s expanded equity backing underscores long-term confidence in Flatiron’s operational execution and strategic vision.
Advisors/counsel: Legal advisors for the transaction included Orrick, Herrington & Sutcliffe and Clean Energy Capital, representing Flatiron Energy, and Faegre Drinker Biddle & Reath serving as counsel to Hull Street Energy.
KEY QUOTES:
“This expanded relationship with HPS, a global leader in infrastructure credit, positions Flatiron to grow on its first-mover and market-leading portfolio in the Northeast and Mid-Atlantic. We are excited to have this flexible and accretive capital to grow the operating base of our independent power producer.”
Dan Myers, Chief Investment Officer, Flatiron Energy
“Since Flatiron’s founding, HSE has supported our rapid growth in our core markets, thanks in part to their deep understanding of power markets, especially in Massachusetts and New York. We appreciate HSE’s expanded support and look forward to leveraging our combined expertise and resources to continue our growth.”
Rob Brink, Chief Financial Officer and Co-Founder, Flatiron Energy
“Hull Street Energy has a successful track record investing capital in the North American power sector as it navigates rising demand and increasing operational complexity. We value the Flatiron team’s deep industry experience, strategic insight and meticulous execution. The portfolio they are building will provide essential firming resources to increasingly power constrained regions and aligns well with our mission.”
Sarah Wright, Founder and Managing Partner, Hull Street Energy
