New Industry Products

Low Cost, Long-Duration Energy Storage

February 21, 2017 by Jeff Shepard

Primus Power announced production of EnergyPod 2, the second-generation of its long duration, fade-free flow battery. Primus' stationary battery systems are scalable from 25kW to 25MW and are intended to serve the energy storage needs of corporations and utilities. With a five-hour duration and lab-certified 20-year life, EnergyPod 2 delivers a total cost of ownership up to 50% less than leading conventional lithium-ion battery systems.

EnergyPod 2 directly addresses electricity cost, stability, and sustainability. Commercial and industrial customers face high electricity bills during peak power periods. Long duration energy storage can significantly reduce demand charges by shifting load from on-peak times to off-peak times.

Leading companies like Microsoft are testing Primus systems for peak shaving applications at a Redmond, Washington data center. Microsoft’s Bill Gates identified flow batteries as a breakthrough energy technology, writing “a flow battery could last for decades and the rechargeable electrolyte liquid could last indefinitely … unlike lithium-ion batteries whose capacity falls by half after 1,500 cycles.”

Multiple hours of battery power are required to bridge power outages and are a critical component of industrial microgrids. In late 2016 the Primus and Raytheon-built microgrid at the Marine Corps Air Station in Miramar, California was awarded Energy and Water Project of the Year from the U.S. Department of Defense’s Environmental Security Technology Certification Program.

Regulatory agencies around the world recognize the growing need for storage systems with longer duration. The California Public Utility Commission wrote in a recent staff report that “more hours of peak shifting capability would be more effective in removing generated energy from the grid at peak supply times and injecting it into the grid at peak demand times.” In lockstep, planned updates to California’s Self Generation Incentive Program encourage five and six-hour battery systems by rewarding additional discharge hours with additional incentive dollars.

Utilities can use long duration batteries instead of fossil-based systems to satisfy peak power needs, defer costly system upgrades, and shift mid-day oversupply of renewable photovoltaic generation to evening peak periods. Modular battery systems, like EnergyPod 2, offer compelling economics compared to distribution substation upgrades, especially in crowded urban areas. Primus is shipping systems to U.S. and international utilities, including Puget Sound Energy in Washington State.

EnergyPod 2 benefits from experience gained with field installations of the first generation EnergyPod. Customer feedback has inspired engineering optimizations that allow EnergyPod 2 to deliver an industry-leading levelized cost of storage. Unlike lithium-ion based systems, EnergyPod 2 has no fire concerns and energy capacity does not fade over time. Its optimized design eliminates expensive and life-limiting components – membranes/separators, graphite electrodes, and complex plumbing – that spoil the economics of other flow batteries. EnergyPod 2 is shipping to customers worldwide.