Flow Battery Vs. Tesla Battery Smackdown Looming

June 21st, 2015 by Tina Casey

Yes, they went there. A little-known startup energy storage company called UET just announced a major milestone for its latest flow battery project, and the folks over there couldn’t resist the opportunity to take a poke at the much-publicized Tesla battery, too.

The new UET flow battery is part of a major energy storage project supported by the US Energy Department. The goal is to compare and contrast the performance of flow batteries with lithium-ion batteries — such as the Tesla battery — when it comes to utility-scale performance and grid integration. So, hold on to your hats, this could get interesting.

Energy Storage & Flow Batteries

For those of you new to the topic, the energy storage market is set to take off like a rocket, running apace with the renewable energy market and the boom in electric vehicle sales.

Since wind and solar energy come and go, energy storage fills a critical gap in terms of availability and reliability. That goes for utility-scale operations and the booming small-scale sector consisting of homes, businesses, and other relatively small users.

So far, lithium-ion (Li-ion) technology has staked a claim to the gold standard for energy storage in terms of performance relative to cost. To gild the lily, Li-ion batteries are easily scalable — hence the Tesla Motors Li-ion battery and coming Gigafactory.

Best known for its application to the already-legendary Tesla electric vehicle, the Tesla battery was recently introduced to the small-scale stationary energy storage market in the form of the Powerwall battery, and the company is also diving into the utility-scale market.







However, other energy storage technologies have an eye on the prize as well, which brings us to redox flow batteries (redox is fancyspeak for the transfer of electrons).

“Flow” literally describes how flow batteries work. They consist of two tanks of liquid, which simply sit there until needed. When pumped into a reactor, the two solutions flow adjacent to each other and generate a charge.

Earlier versions were costly, inefficient affairs but in recent years flow battery technology has leaped several hurdles. The main driver here in the US has been the Energy Department’s Pacific Northwest National Laboratory (PNNL).

The UET Flow Battery

That brings us to UET, which is short for UniEnergy Technologies.

The guts of the UET flow battery were developed at PNNL, which engineered a flow battery based on vanadium (vanadium is a silvery gray transition metal, also known as a micronutrient).

PNNL’s breakthrough was to introduce hydrochloric acid into the electrolyte solution. Conventional flow batteries use sulfuric acid, and PNNL found an increase of about 70% in storage capacity when both acids are used.

In addition, the use of two acids enabled the battery to function efficiently at a far greater range of temperatures. As for lifecycle costs, one advantage of vanadium flow batteries is the 100% recyclability of the vanadium.

In 2012, we took note when UET won a licensing agreement to cross the technology into commercial use, specifically aimed at wind energy. Here’s what the Energy Department had to say back then:

The redox flow battery is well-suited for storing intermittent, renewable energy on the electricity grid. The technology can help balance supply and demand, prevent disruptions and meet the grid’s varying load requirements…

Redox flow batteries can also help utilities during times of peak demand on the grid, providing additional power when it is needed. Successful commercialization of DOE-sponsored technology development, such as this, is vital for creating the grid of the future, and sustaining U.S. leadership in advanced technology.

Let’s note for the record that Tesla Motors can also thank us taxpayers for its success. In 2010, the company received a $365 million federal loan to crank up production of its Model S electric vehicle (Tesla paid off the loan far ahead of schedule, btw).

Where were we? Oh, right. UET’s big new announcement. The company is involved in a three-part Energy Department–sponsored smart grid energy storage project in Washington State, which is designed to demonstrate high-efficiency systems for tapping into the region’s wind energy resources.

The project is set up to include both Li-on and flow battery technology. UET was tapped to provide a flow battery for Avista Utilities, which was assigned to develop a “smart campus” microgrid with Washington State University in Pullman. One major end-user will be the employee-owned electric power systems company Schweitzer Engineering Laboratories.

The battery was delivered earlier this year and the new announcement confirms that the shakedown period is over, and it is now fully owned by Avista.

Here’s the subtle dig at the Tesla battery from company CEO Gary Yang from the press release:

…UET is not shy to say it has the best grid-scale energy storage solution at the best levelized cost, maximizing value for the customer.

Actually, UET is hardly being subtle about it. Back up a couple of graphs in the press release and you’ll find this nugget:

The Uni.System’s levelized cost ($/total GWh delivered over 20 year life) is multiple times lower than the cost of lithium ion systems such as Tesla. Those have limited availability of their energy, degrade in capacity, are flammable, and have ¼ to ½ the lifetime of the Uni.System.

Is that the sound of a dropping microphone we hear?

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Image: Courtesy of PNNL.









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