Page 39 - Energize June 2022

VIEWS AND OPINION

In a VRFB, extending the energy Energize: The examples you give are for large industries at utility scale. Are VRFBs unsuitable
duration becomes cheaper than or too expensive for smaller applications?
extending the energy availability in other
technologies. That means that extending MN: It’s not so much the price. It has more to do with energy density. VRFBs are large,
the battery’s delivery of energy time would high-power batteries designed for utility, industrial and commercial applications. They are
be cheaper as a levelised cost. Equally, ideal for use at renewable energy sites where they can smooth out variability of supply to
costs can be reduced by increasing the the grid or local load. The smallest VRFB I’ve seen is 10 kW, about 40 kWh. That’s at least
charge-discharge cycle of the battery. For twice as much as a residential user would need. These batteries are not meant to be small
example, at an installation in the UK, the – the smallest one you could get is about 2,5kVA. That size is determined by the size of the
battery is charged and discharged three cell stack. That’s where the ion exchange happens, and that’s where the charge-discharge
times a day. process takes place. Some VRFB battery makers have large stacks of 30 kVA per module. A
group of these would be packed together into a shipping container to form a large battery.
Energize: Why would they do that? Other manufacturers offer smaller modules (typically 2,5 kVA or 5 kVA).

MN: They do so because in that liberalised Energize: How would South Africa benefit from the growth of VRFBs?
market the energy supplier can make
more money by supplying power from his MN: Bushveld Minerals mines and supplies about 3,5% of the world’s vanadium in South
battery and recharging it so frequently. It Africa. In total, South Africa supplies around 7% of the world’s vanadium. The country has
has nothing to do with the battery being the highest grades and the third largest resource base for vanadium in the world.
too small for the application. It’s purely We believe that South Africa has excellent opportunities for growth in energy storage.
a matter of economics. And it’s only In 2020, South Africa was the sixth-largest market for residential energy storage, with 185
practically possible with a VRFB. Usually, MWh of deployments, according to IHS Markit. It ranked behind Italy and ahead of the UK.
one wants a VRFB for long duration storage, According to Bushveld’s own analysis, South Africa may be one of the top-five utility energy
so the example above is a unique case storage markets in 2022.
where the client uses it in heavy cycling.
Over 1440 MW of utility procurement has already been announced, including:
Energize: You mentioned long-duration • 350 MW from the first phase of the World Bank-funded Eskom battery procurement
energy storage. Does that mean that the programme (already tendered).
VRFB does not self-discharge? • 578 MW from storage co-located with renewable energy in seven awarded projects in H1
2021, under South Africa’s Risk Mitigation Independent Power Procurement (“RMIPP”)
MN: When I speak of long-duration programme.
storage, I am referring to daily (6 to • 513 MW in new tenders announced by the Department of Mineral Resources and Energy
10 hours) as opposed to 2 to 4 hours for H2 2022 that are included in the South African Government’s Integrated Resource Plan.
of storage. The battery does not self-
discharge because of the two-tank system. Energize: How could VRFBs help to ease South Africa’s energy shortage?
The energy stored in the electrolyte is not
connected to the electrode of the battery, MN: Standalone battery energy storage systems (BESS) solutions can be dynamically sized to suit
so there’s no continuous reaction. But any long-duration storage requirement, typically sized from 100 kW / 400 kWh to 40 MW /
that’s not why a VRFB is a long-duration 160 MWh. Standalone solutions are usually made up of multiple containerised units and can
battery. A VRFB is a long-duration battery stand in any convenient location within, or even outside of, a customer’s existing plant. Bushveld
because you can scale power and energy Energy has worked with most of the suppliers of containerised solutions, can identify the correct
separately. So, if you were to need 10 supplier for your specific application or location and even develop the entire project.
hours of storage, using a VRFB would be
a lot cheaper than using any other kind of Energize: How would an independent power producer (IPP) benefit from using a VRFB?
battery technology.
A typical application is for peak MN: VRFBs are particularly suited to IPP applications as they can achieve both the short
shaving. In South Africa we have a 5 hour duration load levelling and the long duration dispatchability requirements. In addition, VRFBs
peak tariff, so you could use a 5 or 6 hour are capable of providing power quality improvements and other ancillary services to the IPP
battery to achieve this. and thereby to the grid operator.
Consider a mine in a remote off-grid Often IPPs are constrained by the transmission capacity of outgoing transmission lines,
area. If sufficient solar PV is available, the so that part of their output must be spilled. This excess energy could be stored in a VRFB for
PV could power the mine and charge the later transmission when current output is lower and there is capacity on the line.
battery during the day and the battery
would discharge power to keep the mine Contact Kesebone Maema, Bushveld Minerals, Kesebone.Maema@bushveldminerals.com,
working after sunset. https://www.bushveldminerals.com

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