Two high-profile investors in this round are Princeton, N.J.-based NRG Energy, Inc. (NYSE: NRG) and Fisher Brothers.

NEW YORK--Eos Energy Storage announced today the completion of its $15 million Series B financing round with participation from a syndicate of 21 strategic and financial investors. The round supports Eos's commercialization of its safe, low-cost and long-lasting grid-scale battery technology.

Eos's Aurora grid-scale energy storage product has been specifically engineered to help utilities operate more efficiently and create savings for consumers by time-shifting peak energy demand while providing greater resilience to the electricity grid. Eos will begin deploying the Aurora in 2014. The company is in advanced discussions with several states regarding the location of its pilot manufacturing facilities.

Two high-profile investors in this round are Princeton, N.J.-based NRG Energy, Inc. (NYSE: NRG) and Fisher Brothers. NRG delivers cleaner and smarter energy choices for its customers, backed by the nation's largest independent power generation portfolio of fossil fuel, nuclear, solar and wind facilities. NRG invests in emerging technologies and high-growth companies as part of its goal to deliver innovative solutions. Eos is NRG's first investment in the energy storage industry.

Fisher Brothers is a privately owned New York City-based real estate firm which also owns Plaza Construction, a contractor with experience building urban power plants and renewable energy projects. Fisher Brothers is also a co-sponsor of the City Investment Fund (with Morgan Stanley), a founding member of Perella Weinberg Partners and a founding partner of Convergent Energy + Power, an energy storage asset development company with a pipeline of projects in New York, California and elsewhere.

"Eos's technology is of strategic interest to NRG as we seek to enhance the value of our generation assets and evaluate novel energy storage business opportunities," said Denise Wilson, NRG Executive Vice President and President, New Businesses. "We have confidence in Eos's technology, its management team and the compelling value proposition the company will provide to the marketplace."

Winston Fisher, a partner at Fisher Brothers, added, "Energy storage can bring building operations and the electricity grid into the 21st century. Eos's groundbreaking technology will reduce costs for building owners and help integrate renewable energy on the grid. Fisher Brothers's investment in Eos is a natural extension of our commitment to develop energy storage assets benefiting our tenants, the environment and our bottom line."

Eos President Steve Hellman noted, "We could not be more enthusiastic about our collaboration and alignment of interests with NRG, Fisher and our other investors." Michael Oster, Eos CEO, commented, "NRG is a trailblazer in developing and implementing new technologies and Fisher Brothers is also a strategic partner which highlights the behind-the-meter potential of energy storage."

Eos is actively raising capital for its Series C investment round to fund the production and delivery of Aurora energy storage systems to its utility partners in 2014. "With early revenues from sales to our utility partners and a capital efficient manufacturing plan, Eos has a clear and relatively short path to profitability," Hellman said. Hellman added that Eos plans to announce these global utility partners and other prominent strategic relationships in late spring or early summer.

ABOUT EOS ENERGY STORAGE:

Eos is developing a low-cost energy storage solution for electric utilities, with additional applications in the industrial, telecoms and transportation industries. Eos's mission is to produce safe, robust, cost-effective energy storage solutions that are less expensive than incumbent alternatives, such as gas turbines for power generation. Eos is located in Edison, NJ, and New York, NY. More information is available at www.eosenergystorage.com.

ABOUT NRG ENERGY:

A Fortune 500 company, NRG is challenging the U.S. energy industry by becoming the largest developer of solar power, building the first privately-funded electric vehicle charging infrastructure, and providing customers with the most advanced smart energy solutions to better manage their energy use. In addition to 47,000 megawatts of generation capacity, enough to supply nearly 40 million homes, our retail electricity providers – Reliant, Green Mountain Energy and Energy Plus – serve more than two million customers. More information is available at www.nrgenergy.com. Connect with NRG Energy on Facebook and follow us on Twitter @nrgenergy.