Department of Energy

Primus Power’s Flow Battery Powered by $11 Million in Private Investment

June 14, 2011

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 Primus Power's energy cell stack. | Photo Courtesy of Primus Power

Primus Power's energy cell stack. | Photo Courtesy of Primus Power

In February, the Advanced Research Projects Agency-Energy (ARPA-E) announced that six of its projects, which initially received a total of $23.6 million in agency seed funding, had collectively generated more than $100 million in outside private capital investment. ARPA-E recently received the news that another of its performers, Primus Power, has generated $11 million in follow-on funding for its grid-scale storage technology –- 5 times more than ARPA-E’s $2 million investment last year. As Secretary Chu has said about follow-on funding for ARPA-E projects, “This is precisely the innovation leverage that is needed to win the future.”

Primus Power has developed a low-cost, distributed storage flow battery made of tanks filled with high energy density electrolytes that are pumped throughout the battery system. This flow battery can store renewable energy such as wind and solar power and then release that energy into the grid during peak load times. Since renewable energy is intermittent, the ability to store this electricity to balance grid power is becoming significantly more important as renewables become more prevalent in the U.S.

Primus Power is building a farm of flow batteries that promise to offer 25 MW of power for up to 3 hours for the Modesto Irrigation District (Modesto, California’s utility provider). This battery farm will serve as a full-scale demonstration system, and will store the region’s wind-generated energy as well as providing an alternative to fossil-fuel-fired generation.

But Primus Power wanted to take a leap further. Using ARPA-E funding, Primus is researching a next generation technology, which if successful has the potential to drastically improve flow battery technology by developing an inexpensive, extremely durable metal electrode for flow batteries that will significantly enhance the lifespan and lower the cost of the batteries. ARPA-E funding will also go towards developing the process and structure for the metal electrode by leveraging fundamental knowledge on high volume processes currently used in the metals industry. Based on early results from the ARPA-E project, Primus is already making initial plans for subsequent demonstration of its new electrode technology. The latest round of private sector financing will allow the team to develop its first full-scale flow battery system and move quickly towards commercialization.

ARPA-E’s Program Director for its Grid-Scale Rampable Intermittent Dispatchable Storage program, Dr. Mark Johnson, said, “Emerging flow battery technologies promise to dramatically improve the stability of our electricity grid, with these over-the-horizon technologies establishing domestic leadership for energy storage technologies.”