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Advances in vanadium redox battery technology are improving the performance and stability of these energy storage devices. But an engineer at the US Department of Energy’s Pacific Northwest National Laboratory says costs need to drop before the battery is commercially viable.
By Karan Kumar — Exclusive to Vanadium Investing News
Vanadium redox batteries, which use vanadium ions to store energy and integrate solar and wind power into the electric grid, are at least five years away from commercialization as their cost is still too high.
Research by scientists at the Department of Energy’s Pacific Northwest National Laboratory (PNNL) has helped move vanadium redox batteries closer to commercialization. PNNL’s research shows that a new electrolyte mix that uses both hydrochloric and sulfuric acid increases energy storage in the battery by nearly 70 percent, allowing the upgraded battery to improve the electric grid’s reliability and helping connect more wind turbines and solar panels to the grid.
Vincent Sprenkle, chief engineer in energy materials at PNNL, told Vanadium Investing News in an interview that the lifecycle cost of the battery is still too high for it to be commercially viable.
Tell us a little bit about what kind of costs are currently associated with vanadium redox batteries. How much do they need to come down?
Cost dictates our research. The primary metric is dollars per KW hour per cycle. Right now pump hydro costs $0.01 per KW hour per cycle. For vanadium batteries, it is $0.08 per KW hour per cycle. We think a suitable target for vanadium batteries is less than $0.04 per KW hour per cycle. At this price, these batteries can be relevant and have application.
What was the performance problem associated with vanadium redox batteries and how did PNNL’s research help change that?
Redox batteries have been around for a while, since when NASA developed them in the 1970s. One of the primary issues with vanadium redox batteries is how many times you can charge and recharge them without a significant loss in performance. If you charge and recharge once a day, you’re looking at 365 cycles. You cannot have a battery degrade over all those cycles and have a 20-year life. The current vanadium battery technology lacked the ability to do long-term cycling without significant degradation. PNNL’s research focused on improving the degradation of the vanadium redox battery’s electrolyte solution mix while increasing the energy you can store in the battery. This ultimately lowers the overall cost of the battery system.
Until the research, there had been some degradation of the electrolyte mix, which degrades with each cycle. Eventually you get to the point where you cannot do any more reactions. PNNL’s development improved that stability in the vanadium redox battery. PNNL’s research focused on the electrolyte solutions, maintaining the energy density, and improving the overall economics of the battery. We made two adjustments: we improved the concentration of the solution. We have the same size tank (for the battery) now but now we get more energy out of the same volume of solution. We have also improved the stability, meaning that the new solution is much more stable over a wide range of conditions.
How long before the vanadium redox battery is commercially available?
I think what you are seeing now is demonstration out there. Many companies are working in this field. The big thing is going to be the stability issue with the battery. It is going to take some time to get these new chemistries incorporated in the battery. I think there is still a lot of effort and research needed to drive the cost down.
I think in the next five years you will see more commercial application. Right now what you are seeing are demonstrations where vanadium redox batteries are application critical – where you cannot have something shut down. What you are going to see, ideally, is systems at the residential and community level, where homeowners can store power and use it when needed.
Do you think vanadium redox batteries hold the potential to revolutionize the way energy is stored?
Yes I do. PNNL is working on three battery technologies for large-scale solar and wind integration: Redox Flow Battery, Na Metal Halide, and low-cost Li-ion. Sodium Sulfur is another potential battery technology being developed. There is no other viable candidate. Vanadium redox batteries are going to change the way we integrate renewable energies into our current grid structure.
One of the unique things about vanadium is that it has multiple oxidation states. It is one of the few elements you can use on both the cathode and the anode. So since the cathode and anode are of the same species, there is less contamination and crossover in the battery. So vanadium is very attractive for this type of application. I can see there being tremendous increase in demand for vanadium as these batteries become commercially viable.
Securities Disclosure: I, Karan Kumar, hold no direct investment interest in any company mentioned in this article.