After a decade of development, a $100 million in funding, and some twists and turns (including a name change), Silicon Valley startup Imergy Power Systems will soon start shipping the next generation of its batteries made from recycled vanadium. The 50-kilowatt battery will be available next month and can store up to 200 kilowatt hours of electricity, using vanadium recycled from mining and power combustion industries as well as environmental waste.
The idea is that customers — like commercial building owners or solar farm developers — can buy these batteries to help lower their monthly energy bills in various ways or help them disconnect from the grid. For example, in Hawaii where electricity is ultra expensive, building owners could charge up the batteries at night, when electricity rates are cheap, and run off of batteries during the day when electricity rates are expensive. Solar farm owners could use the batteries to store electricity from the sun during the day, to be used at night when the sun goes down.
While Imergy was founded 10 years ago as Deeya Energy, it wasn’t until two or three years ago that the company stumbled onto an important tech break through. Imergy’s CTO Majid Keshavarz was able to develop an electrolyte for the battery that can use lower-grade recycled vanadium.
Vanadium batteries that have been invented in the past have had to use pure vanadium, making them an expensive proposition. Pure vanadium also can’t be operated above a certain temperature. But Imergy’s team says its new battery can be made for under $300 per kilowatt hour and also used at up to 131 degrees Fahrenheit. The technology is “game changing,” says Imergy’s new CEO Bill Watkins, who joined the company a year ago, and has previously led Valley companies like LED startup Bridgelux and hard drive maker Seagate.
Imergy’s battery isn’t like a traditional lithium ion battery; it’s called a redox flow battery. Flow batteries have their electrolyte (the substance that acts as the medium for the charging and discharging of the battery) separated out of the battery cell in liquid-filled tanks. The benefits of a flow battery are that it can be cheaper than traditional lithium ion batteries, it can be more flexible (you can add more tanks and electrodes to that type of open system), it can last much longer (the electrolyte doesn’t degrade as fast, if at all in vanadium’s case) and it can provide a longer burst of sustained power.
What’s particularly unique about a vanadium flow battery is that it doesn’t degrade over time. “That’s the outrageous-sounding claim that we’re making,” says Watkins. “The battery lasts forever.” As lithium ion batteries charge and discharge over time they start to lose their capacity to hold a charge after several years because of chemical reactions inherent in the chemistry.
But because vanadium can operate in both negative and positive states, there aren’t chemical reactions introduced by combining two separate chemicals. The battery can just keep going and, when decommissioned, the vanadium can still be reused in some other application.
The battery that Imergy is introducing on Thursday is first using the recycled vanadium, but the company already has dozens of smaller 5 kW units operating in the field, mostly at the sites of off-grid telecom base stations. In rural areas of a country like India, telcos commonly put up a base station that runs off of a diesel generator, which is costly and requires routine maintenance. Imergy’s flow battery can beat a diesel generator on cost over time (including use of diesel fuel).
Now that the startup has what its executives think is a breakthrough technology, they’ve decided it’s time to scale up and deploy the tech. This next-gen battery can store 200 kWh of electricity, and by the middle of next year Imergy hopes to deliver a battery that can store 1 mWh of electricity. Watkins says Imergy already has customers for this first next-gen battery, and they’ll be shipping it next month.
The company is backed by NEA, Technology Partners and Blue Run, and they’ll need more funding to move up into the megawatt scale. Startups that are also selling flow batteries include EnerVault (I visited their first large battery installation earlier this year) and Primus Power (check out the behind-the-scenes at their lab).
Most of the customers for Imergy’s first next-gen battery will be commercial and industrial customers looking to lower their energy bills. But down the road, Watkins sees a vision of grid-free clean power and energy storage for everyone: “In 10 years for the price of a pool, you could be hooked up with solar, a battery and a system to manage it, and get all the energy you need from the sun. It will be a fundamental change for how the world operates.”