
Vanadium-Flow Batteries: The Energy Storage Breakthrough We've Needed - aburan28
http://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-flow-batteries-the-energy-storage-breakthrough-weve-needed/#59107bcc7271
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philipkglass
The cost of storage is the most interesting claim: 5 cents per kWh, amortized
over the system life. If everything else about the article was identical but
the cost was _40_ cents per kWh then this would be just another chemistry
experiment too expensive for widespread use. So I was really hoping to find
more details about the cost number -- what modeling assumptions went into it,
what sort of lifetime is warrantied from the manufacturer, whether the cost is
genuinely based upon current prices or is one of those malleable "in a few
years..." projections.

Everything that they have disclosed, technology-wise, looks believable and
good. But past vanadium redox flow batteries have been fairly expensive per
cycled kWh and I thought that was more about the relatively high price of
vanadium than about the temperature/solubility limits of all-sulfate
electrolytes. If the mixed-acid electrolyte really is the main enabler of the
impressively low claimed cost, I'd like to read how. Mostly I'd like to read
supporting evidence behind the "5 cents" number.

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manicdee
For my purposes anything under $AU0.18/kWh extracted means I can say goodbye
to the grid and imminent surcharge for having PV on my roof.

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out_of_protocol
Usable membrane-less version of flow battery IS the breakthrough. Still, that
article didn't even mention that. Membrane is the weak point of the
technology, it's expensive and with limited resource.

P.S. Technology of flow batteries is _very_ promising (at least for consumers
with size down to cars) but the article is not.

Wiki so much better:
[https://en.wikipedia.org/wiki/Flow_battery](https://en.wikipedia.org/wiki/Flow_battery)

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heisenbit
My understanding of the chemistry is that they are using Vanadium Chloride
which is not listed in the Wikipedia article. What is mentioned in Wikipedia
are membrane cost/stability issues with Bromide. I could imagine the latter is
more reactive but I'm definitely not a chemistry buff.

Their view of the chemistry:

> using a molecule developed at the Pacific Northwest National Laboratory.
> PNNL’s breakthrough was to introduce hydrochloric acid into the electrolyte
> solution,

What I found also newsworthy is that the largest battery soon will be China
with 800MWh. That is a typical US nuclear reactor providing power for 1 hour -
nothing to sneeze at.

What is also newsworthy is the cost which is also an indication that they got
some handle on membrane cost. They are claiming 5cent/kWhr which would be a
game changer as it is lower than generating it.

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mdorazio
Somewhat misleading title. This is an energy storage breakthrough specifically
for utility-scale storage, but will likely never be practical at the scale of
a home or car battery, and definitely never at the scale of electronics. As
the article points out, the big benefits here are longevity, safety, and cost
per kWh stored, not energy density.

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_nedR
Sorry. This is the first time I am hearing about this tech.

Why couldn't it be practical at the scale of a home? Say if you have a large
backyard?

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candiodari
It can be practical at home scale:
[https://www.zcell.com/](https://www.zcell.com/)

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mdorazio
Only kind of. Zcell costs about 4x a Powerwall of the same capacity ($13k USD
vs. $3500 USD) and has the same warranty duration (10 years), which to me
means they're expecting it to last about the same amount of time in normal
use. It's a decent alternative if you don't want Li-ion for some reason, but
definitely not a good solution cost-wise in the home storage space. As others
have pointed out, the benefit of flow batteries is that you can scale the
tanks very large to add capacity without raising the cost too much, whereas
Li-ion type batteries scale cost with capacity fairly linearly.

