IN DEPTH: Storage Eureka moment?

An old mine in the Nevada Desert’s aptly named Eureka County could spark a revolution in industrial-scale battery thinking. And renewable energy would be the biggest beneficiary.

The Gibellini mine, first explored in the 1950s, and being revamped by Canada-based American Vanadium, holds the western hemisphere’s mother lode of vanadium. The silvery-grey transition metal is the key ingredient in a novel flow battery concept that is starting trials at the US National Renewable Energy Laboratory (NREL).

Vanadium flow batteries (VFBs) have been on a slow burn for many years. Nasa worked on designs through the 1970s, and a first commercial unit is credited to the University of New South Wales researcher Maria Skyllas-Kazacos in Australia a decade later. VFB companies are now dotted about the world, among them US-China tie-up Prudent Energy, the UK’s REDT and Thailand’s Cellenium.

As US master sales agent for German engineer Gildemeister, American Vanadium looks to be taking the technology to the next level, building on a portfolio of 65 smaller-scale energy storage systems (ESSs) plugged in across Europe, Asia and Africa. A landmark power back-up project it is installing at the New York Metropolitan Transportation Authority with the state energy office and utility ConEdison brings the technology to the US.

The coming road tests at the NREL in Colorado, however, would prove that American Vanadium’s VFB — known as the CellCube — is ready for prime time. “A number of leading utilities, integrators and developers will be participating,” emphasises American Vanadium chief executive Bill Radvak, whose eccentric CV covers both mining engineering and biotech. A multi-megawatt flagship has been “designated for sale” to a US utility after testing wraps up.

“Vanadiam flow has been suffering for a long time for being new,” he says. “Nasa conceived of a VFB more than 40 years ago. Lithium-ion [the rising star of energy storage] has a jump-start from massive investment through the automotive industry, which they are now transitioning into [ESSs] for the grid. VFBs didn’t have that spending, until now,” adds Radvak, referring to a C$1m ($925,000) private placement in the company in May.

The drain on enthusiasm for VFB technology to this point has been vanadium itself. China holds the lion’s share of global deposits, making it a commodity susceptible to volatility and price spikes.

US-based Navigant Research analyst Sam Jaffe reckons that although there remains “a relatively open and thriving market for vanadium, it will always remain a high-cost material”.

Japanese electrics behemoth Sumitomo, which has hatched a 60MWh mega-VFB, is expected to become the biggest player in the short term, having forged industrial relationships that ensure “it has no vanadium supply constraints, even though it doesn’t own any vanadium assets”.

Radvak notes: “There are 100 companies doing vanadium flow research in China. Nothing commercial yet, but it is coming.”

American Vanadium ’s ace in the hole is Gibellini. A 2011 feasibility study green-lighted the project, which will be an open-pit heap leach set-up that will pull 5,170 tonnes of vanadium out of the ground each year, translating into 5% of current global demand.

“Three years ago, a market didn’t really exist,” says Radvak. “We had this very clean [low iron-ore content] vanadium deposit with the potential to be used to create great quantities of electrolyte [for VFBs] but needed to find a commercial means to do it. With the CellCube we are shifting our mission to help lead the creation of the energy multi-hour industrial bulk storage — six, eight, 12 hours. This is the domain of VFBs.”

For industrial-scale renewables, the beauty of the VFB is its 20-millisecond reaction time and its modularity. The CellCube comes in 400kWh-1.6MW units that can be stacked, Lego-like, to handle the “peak shaving” and bulk “dispatchable” storage demands of developments the size of utility-scale wind and solar farms.

The magic numbers for VFBs’ commercial take-off, according to US Department of Energy targets, are a capital cost of ­$250 per kWh and a levelised cost of energy of $0.20/kWh. ESS designers including EnerVault, Imergy and American Vanadium say this is within sight.

“Because of the reliable efficiency of these systems over the long haul — say, 20-25 years — when you evaluate the cost of these batteries over their lifetime, its pretty extraordinary,” Radvak explains.

A question mark still hangs over the future of VFBs, however: the falling price of lithium-ion technology. But there is little doubt about the overall next-generation global ESS market, which Navigant believes will mushroom from $182m this year to $9.4bn in 2023. And VFBs are on track to have a place at the grid storage top table.

“VFBs have been around for more than a decade, but are starting to gain some momentum thanks to increased interest in grid storage,” observes Jaffe.

“However, they face a big uphill climb to garner market share because of the dramatic drop in price of lithium-ion batteries, which are now significantly cheaper than VFBs [which use an expensive membrane technology].

“Nevertheless, there will be a market for VFBs and they will occupy a niche in the grid storage business, especially for very long-duration storage requirements.”

Given that the technology is fundamentally proven for commercialisation, he adds, there are no performance milestones still to be passed. Price reduction is the only show-stopper.

“For VFBs to have a chance to compete with lithium-ion,” says Jaffe, “it will have to get cheaper than

current capital costs [about $500/kWh]. That hasn’t happened — yet.”