The choice of battery storage technologies in support of solar energy supply is broadening to suit a variety of emerging applications. VSUN has just made its first power play for vanadium-redox-flow batteries in the off-grid residential market.
V-Flow’s 10 kW/100 kWh VRFB has twice the capacity of the system installed at Hyden in Southwest WA.
VSUN Energy, an organisation formed with the express intent of increasing awareness of the benefits of vanadium-redox flow batteries (VRFB) has taken to selling systems using the technology; its first residential case study came about because equipping a new farmhouse with a VRFB-based standalone power system was cheaper than connecting that rural home to the grid — nevermind the savings that will ensue as the farm lives through its first quarter without receiving a power bill.
The standalone power system (SPS) tailored for this property consists of 12 kW of solar PV, a 5 kW/30 kWh VRFB with a maximum discharge of 7 kW; an Australian-made Selectronic inverter and an 18 KVa diesel redundancy back-up system. The SPS is designed to provide an uninterrupted, clean, safe source of energy, primarily generated by direct and stored solar energy.
VSUN Business Development Manager, Zamien Sumich tells pv magazine the system is currently more than adequate to supply a self-sufficient household, with a cool room to sustain the family in between visits to distant shops, and some farming machinery.
But there are other aspects of vanadium-flow batteries that make them suited to remote or rural life in Australia. For example, says Surich, they can operate in a wide range of temperatures without the need for heating or cooling.
Charging with positives
They’re non-flammable, so cannot start a house fire, or a bushfire. In this regard they’re also a step up from poles-and-wires grid connection — even accumulated dust when mixed with rain water on electricity wires can cause pole-top fires that may spark bigger conflagrations or cause loss of power.
VRFBs also offer virtually unlimited cycling, which makes them ideal for mining applications where constant electricity supply is crucial and variable renewable generation may require frequent fast battery response; and for VPPs where the operator wants to participate in FCAS or arbitrage markets, and may want to cycle its fleet of residential batteries a couple of times a day — such use would radically shorten the life of currently more popular battery technologies.
In addition, says Sumich, “The internal electrolyte solution in VRFB batteries doesn’t degrade,” so they can can continue to provide storage long after the common warranty period of 20 years. Of course, he adds, that because the battery is a machine, some moving parts such as pumps that move the electrolytes through a core of positive and negative electrodes may need to be replaced, but remote monitoring and annual maintenance checks can ensure continuous operation. A VRFB shifts vanadium ions between different oxidation states to store and release chemical energy.
Although VRFBs easily keep their cool, there’s a bit of heat in the Australian vanadium field. Australian mining technology company TNG Limited, which owns the world’s most advanced vanadium project, Mount Peake Vanadium-Titanium-Iron Project , 230km north of Alice Springs in the Northern Territory, this month also established a new Vanadium Redox Flow Battery (VRFB) business unit as the company looks to rapidly expand its green-energy sector.
The ASX-listed parent company of VSUN, Australian Vanadium Limited (ASX:AVL) is looking to develop a primary vanadium mine in Western Australia, an endeavour granted “major project status’ by the Federal Government in 2019. “They’re about 18 months to two years away from that,” says Sumich, “but they created VSUN Energy to grow a secondary market in battery technology for vanadium, which is primarily used in steel hardening”.
Creating a value-adding industry on home ground
Vanadium Australia wants to be vertically integrated into the local market, says Sumich. He explains, “At the moment, you mine the stuff and there is a little bit of processing on shore in Australia but most of it is shipped offshore to Southeast Asia to value add for the US market.”
But with 30% to 60% of the CapEx value of VFRB batteries concentrated in the electrolyte, “by digging it up locally, processing it locally and manufacturing the electrolyte locally, you value add to the Australian economy which is a big thing at the moment, for job creation”, he says.
VSUN is agnostic as to the VRFB battery supplier. On larger storage projects it has worked with EPCs and solar providers simply to promote their understanding of VRFB capabilities. “Our primary focus,” says this Business Development Manager, “has been to create a demand for the electrolyte that goes into these batteries.”
VSUN now operates as an integrator, selecting vanadium batteries from different manufacturers to suit smaller and larger applications.
The Hyden battery is supplied by V-Flow Tech, a Singapore-based manufacturer, and VSUN Energy will now sell V-Flow products from 5 kW/30 kWh size with a lifespan of 25 years into the off-grid and residential settings.
Big footprint
One potential drawback to residential deployment of vanadium battery technology is system size. The system deployed at Hyden measures 1.5 x 1.7 metres x 2 metres in height, and weighs approximately three tonnes, which has little impact in a rural setting, but may pose a greater challenge in suburban environments. That said, VSUN maintains it must be considered as a long-life piece of infrastructure, that displaces other infrastructure, such as poles and wires.
Sumich estimates there are currently seven or eight vanadium-flow batteries deployed in Australia, including one in an offgrid application on Queensland’s Heron Island. In Japan, a 60 MWh battery has proven to be worth its vanadium salts, operating for five years without degradation. And the world’s largest VRFB, at 800 MWh, is due to be completed this year in China.
The technology is scalable, with the Hyden farm application currently supplied in single-phase design, but the battery, like the solar system can be expanded and/or redesigned for 3-phase supply as the demands of the property grow.
The V-Flow battery provides for the small to medium-sized off-grid application, and VSUN is working with a VRFB manufacturer based in China to provide another residential-ready system. It has projects in the works with Horizon Power, providing off-grid energy to remote communities. And it’s working with mining companies to appraise them of the high-cycling tolerance of the VRFB technology.
“As a whole,” says Sumich, “we want to build that understanding in market that this technology has its place, and there are applications where it’s better suited than other technologies.”
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