Vanadium flow batteries have gotten lots of interest because vanadium has 4 oxidation states, so the positive and negative electrolyte tanks have distinct charged and discharged chemistries. This adds a ton of flexibility to usage from multiple cycles per day to seasonal storage while the battery is still operating daily.<p>Manufacturers are advertising 20k cycles vs 6-7k for Li-ion, but in theory, flow batteries can last forever with maintenance.
Since TFA didn't really explain what a "flow" battery is: <a href="https://en.wikipedia.org/wiki/Vanadium_redox_battery" rel="nofollow">https://en.wikipedia.org/wiki/Vanadium_redox_battery</a>
The mix of lithium ion and flow batteries here (50MWh of the former vs. 5MWh of the latter) kind of makes this feel like a proof of concept to me on the flow battery side -- I'd sort of expect the reverse, and to want to mostly lean on the flow batteries because of their suitability for long-duration storage and their tolerance of lots and lots of cycles, and mostly only use the lithium ion when you needed lots of power or to handle rapid changes in demand. But maybe I misunderstand the dynamics here?
This is a very interesting development. 55MWh is a drop in the bucket at grid scale but it definitely is a step forward if the installation performs as designed over a longer period of time without reliability issues.<p>For comparison purposes, also in the UK, Cruachan Dam has 7+ GWh worth of (pumped) storage, but this one even in its present state should be able to spin up even faster (though Cruachan Dam is <i>very</i> impressive in that respect).
Why is this news? It's a 5MWh vanadium flow battery. Another country put online a 800MWh vanadium flow battery (160x larger) this year [1].<p>> Not only will this be the largest directly-transmission-connected battery installed in the UK to date, <i>it will be the largest vanadium flow + lithium-ion hybrid battery ever deployed.</i><p>This is like boasting you have the world first, largest ever potato+nuclear reactor energy source by throwing a potato in an existing nuclear reactor. Good PR for securing the next contract from dimwitted bureaucrats, I guess, but hardly a genuine exposition of cutting-edge technological development.<p>[1] - <a href="https://www.power-technology.com/marketdata/dalian-uet-rongke-power-battery-energy-storage-system-china/" rel="nofollow">https://www.power-technology.com/marketdata/dalian-uet-rongk...</a>
Spec sheet of a VS3-022 container (note website slow response - hug of death?): <a href="https://invinity.com/wp-content/uploads/2021/10/Invinity-VS3-022-Vanadium-Flow-Battery-Data-Sheet-MAR00016-2021-09.pdf" rel="nofollow">https://invinity.com/wp-content/uploads/2021/10/Invinity-VS3...</a><p><pre><code> Non-flammable Safe by design 25 year lifespan Unlimited cycles Lowest LCOS High recyclability
CUMULATIVE ENERGY DELIVERED OVER TIME
INVINITY VS3-022 3783000kWh versus LITHIUM 973kWh
(Assumptions: 220 kWh DC capacity installed, 2 cycles per day, 100% DoD per cycle, 365 days a year).
[Note corrected for typo in PDF: 3,783.000kWh should be 3,783,000kWh]
PERFORMANCE SPECIFICATIONS
Ambient Operating Temperature 25°F to 110°F (-5°C to 45°C)
Nameplate Rating DC Voltage 1000 VDC
Operating Voltage, Nominal 850 VDC
Operating Voltage Range, Full Power 750 to 950 VDC
Max. Continuous DC Current ±104 A
Max. Continuous DC Power 78 kW
Energy Storage Capacity 220 kWh
Energy Storage Duration 2.5 hours @ 78 kW 4 hours @ 56 kW 8 hours @ 28 kW
Max. Recommended Depth of Discharge 100%
Cycle Life > 20,000 cycles
Lifetime Throughput 3,783 MWh
Annual Capacity Degradation < 0.5% per year
Max. DC Round Trip Efficiency (RTE) > 78%
Annual DC RTE Degradation < 0.1% per year</code></pre>
They don't say why it's combined with traditional lithium ion - wasn't one of the promises of Flow that they can scale it up for longer storage just by adding more liquid?
27x 20ft shipping containers combine to form a 5mw vanadium flow battery buffering a 50mw lithium battery. Which is interesting but the fact it's not 100% flow battery suggest lithium must still be sufficiently cheaper to overcome its shorter life.
Its like no one has heard of Stocking Pelham from 4 years ago:<p><a href="https://stateraenergy.co.uk/Energy%20Storage%20Facility/pelham-storage/" rel="nofollow">https://stateraenergy.co.uk/Energy%20Storage%20Facility/pelh...</a>