Since the basic patent protection of redox flow batteries expired over a decade ago, dozens of technology companies have been running to develop the technology and cut costs. In many ways they have succeeded. Matt Harper, president of Avalon Battery, says prices offered by leading manufacturers have come down 80% in less than five years. Lazard, an asset manager, estimates that the leveled costs of storing electricity in some redox power projects now overlap with lithium-ion batteries, the main competition. This year, sales of vanadium flow batteries, the most established redox flow technology on the market, have grown from double digits to just over 200 MWh of installed storage capacity.
Despite these achievements, Alex Eller, an analyst at Navigant points out that redox flow batteries have not yet drained the energy market. He says that most of the 7,000 MWh of grid power coming online this year will be replenished by lithium-ion batteries, followed by pumped hydro and other established storage technologies, with flow batteries behind.
has been relatively small, ”said Eller. "We're just starting to see big commercial projects in the works." Although he sees many obstacles still facing the new redox flow industry, Eller is also convinced of the technology's potential to reduce the cost of renewable energy storage.  Zero Degradation
Reducing the record-low prices set by lithium-ion batteries will not be a small challenge. In recent years, global electronics brands including Samsung, LG and Panasonic have streamlined assembly lines that can produce gigawatt-hour lithium-ion batteries every year. Prices have fallen faster than expected, and weak demand for electric vehicles has led to a plethora of cells being sold at cutthroat prices to save electricity online.
Tough as competition can be, flow batteries have an ace up their sleeve. Unlike the lithium-ion batteries they compete with, their electrolytes are not degraded. According to Richard Wills at the University of Southampton, what sets technology apart is its architecture. Instead of distributing electrolytes in each cell, a flow battery separates electrolytes into external tanks and pumps the liquid through active elements that store and deliver energy. At first glance, the device looks more like a chemical treatment plant than an AA battery.
Redox flow technology presents new challenges. To work, these batteries need pumps and aqueous electrolytes that have relatively low energy density. They also reduce the efficiency of the energy conversion process, they are unmanageable for most modes of transport, and they increase the floor space needed to house components.
But Wills says that redox flow technology can also charge and drain batteries without detracting from their behavior. "The reactions carried out in redox flow batteries are the transfer of electron surfaces that are less susceptible to degradation of electrodes and current collectors," Wills said, adding that the large volume of aqueous electrolyte pumped through the cell stack also helps dissipate heat, a important load on the materials and notorious fire hazard in lithium-ion batteries. Cooler operation leads to higher safety margins, longer equipment life and lower maintenance costs. On paper, this makes flow batteries safer than Li-ion technology and cheaper during a storage project.
"We have run a vanadium flow battery through 24,000 hours of very aggressive cycles and still cannot measure any deterioration in battery performance," said Alex Au, CTO of Nextracker. Three years ago, the US tracker provider added energy storage solutions to its Au catalog, testing more than 40 technologies internally to select products that are compatible with lifelike fluctuations in power grid demand. The Vanadium flow batteries made by Avalon Battery made the cut. "They can even boast less degradation and a better warranty than any solar module on the market today," Au said.
Vanadium Rental Store
Back at Navigant, Alex Or says that extended life and reliability of flow batteries should, in principle, recommend the technology for withdrawn electricity generators, especially solar arrays, which are concerned with storing large amounts of electricity for several hours at the top of the wholesale market. However, the limited registration of large-scale flow battery projects has so far restricted their distribution.
"Flow batteries face a serious problem of trust," said Eller. He explains that the most important companies that buy batteries today are risk-averse project developers. These procurement teams will ensure that the manufacturer of the battery of their choice still exists in ten years, in case they need to replace the wrong purchase. As a result, they favor working with reputable lithium-ion behemoths, rather than launching redox flow pioneers, regardless of the project's long-term cost projections.
In a similar conservation view, no established lithium-ion manufacturer has so far ventured into the redox flow battery business. Or bet that their reluctance is caused by market uncertainty. It remains unclear which version of redox flow technology comes out on top. "Floating batteries that use vanadium electrolytes are very good, but vanadium is expensive," he says. Commodity costs are already inflating investment for vanadium power projects by over 30% and investors fear that fluctuations in commodity prices could stifle supply chains.
Matt Harper of Avalon Battery claims that creative financing and vanadium leasing schemes create vanadium. flow projects more bankable. To reassure annoying buyers, manufacturers have begun to secure third-party guarantees. Insurance companies such as New Energy Risk in the United States will cover declines in battery performance over 20 years of life for a redox flow project, even if the battery manufacturer goes out of business. These contracts effectively guarantee returns from an energy storage project so the developer can rely on the insurance company, even though they still get to know the manufacturer.
Similarly, the business solution mitigates the risk of vanadium supply chains by allowing customers and battery manufacturers to lease their electrolyte. Vanadium producers, including Glencore and Bushveld Energy, are prepared to rent out the metal and recycle it, with part of the capital expenditure on the project. "The vanadium electrolyte does not degrade and can be fully recovered when the battery life is over," said Mikhail Nikoramov, President and CEO of Bushveld Energy.
Harper claims that these advances have brought the vanadium power industry to the same inflection point as equipped lithium-ion manufacturers in the 1990s when consumer electronics went into mass production. So far, redox flow batteries have filled niche programs, typically where fire safety is of particular importance. But like the prices of lithium-ion batteries, Harper expects redox flow technology to storm the desktop storage market. He estimates that this growth could reduce Avalon Battery's prices below $ 40 / MWh, turning solar energy into "a truly transmissible asset capable of displacing all other power sources on the grid." In his view, the key to cutting costs is a mature supply chain and standardization.
This is good news for the 70,000 square foot factory that is taking shape in Saudi Arabia. Opening in 2020 will deliver over 1 GWh of redox flow storage capacity to the market each year, providing unparalleled economies of scale to an industry that has so far had to do with customized solutions as it fights against mass-produced competition.
The Saudi plant will drain vanadium flow batteries developed by Schmid, a German PV equipment supplier with 150 years of industrial engineering experience. The family business branched into redox flow batteries in 2011, commercialized the first vanadium flow battery in 2014 and set out in search of partners to scale up production.
Schmid signed an agreement this year with RIWAQ, a Saudi construction company, and Nusaned Investment, a subsidiary of the Saudi petrochemical giant Sabic, which funds technologies that support policies put out by Saudi authorities. In 2016, the Kingdom announced its Vision 2030 plan to reduce its national dependence on oil revenues, particularly through massive investments in renewable energy. The venture brings together some of the most revered veterans in the float battery industry with exceptionally deep-pocketed investors.
"The new Schmid agreement in Saudi Arabia is very exciting," said Maria Skyllas-Kazacos, who invented redox flow technology in the 1980s. She adds that the plant "will definitely help provide the scale of production needed to further reduce costs."