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Cost of energy storage sinking like a stone: Imergy Energy Systems shaves down price of its vanadium flow battery series from $500 per kWh to $300.


Shot Of Adrenalin For Super-Hot Solar Market: Vanadium Flow Batteries

Cost of energy storage sinking like a stone: Imergy Energy Systems shaves down price of its vanadium flow battery series from $500 per kWh to $300.

We sure took notice of the latest federal report showing that the cost of solar power is rocketing downwards, but there’s a hitch: what about the cost of energy storage? After all, raw solar energy is an intermittent source. Bringing down the installed cost of solar power systems is half the challenge. The other half is bringing down the cost of energy storage technologies that make solar (and wind, for that matter), an at-your-fingertips form of energy on par with stocking up on coal, oil, or natural gas in terms of both cost and reliability.

Here to help un-hitch the hitch is Imergy Power Systems. The company first crossed our radar with its proprietary flow battery based on material reclaimed from mine tailings and derelict oil wells. Today Imergy is announcing the introduction of its new ESP30 series, which according to its press materials will cut the cost of its signature flow batteries from $500 per kilowatt hour to less than $300 per kilowatt hour.

vanadium flow battery energy storage

“Warp Core” by Matthew Ganon via, cc license.

Cost Of Energy Storage Sinking Like A Stone…

The latest report on solar energy costs came from the Energy Department’s National Renewable Energy Laboratory earlier this week. We also noted recently that the cost of energy storage is plummeting, and while the figure of $300 cited by Imergy doesn’t beat some of the other technologies that have crossed our radar, it is getting pretty close to the Energy Department’s near term goal of $250 per kWh for grid energy storage (see p. 32).

It’s also worth keeping in mind that flow batteries have an important lifecycle advantage over some other energy storage technologies, including the current gold standard, lithium-ion batteries.

Flow batteries literally refer to the charge generated as two fluids flow adjacent to each other (see here, here, and here for some examples emerging in the research stage).

Flow batteries score points for longevity, as they do not degrade over time as do lithium-ion batteries, for example.


That makes flow batteries ideal for intermittent energy storage. They can sit idle for long periods without losing their charge, and they can be revved up to speed almost instantly when called into action.

Another key advantage of flow batteries is ease of scalability. Enlarging the size of the battery is primarily a matter of increasing the size of storage tanks for the fluids.

Until recently, typical flow batteries were bulky affairs, but along with lower costs more compact systems have been emerging, to the extent that they could even find application for EV batteries.

The Imergy ESP30 Flow Battery

With all that in mind, let’s take a closer look at the ESP30.

Vanadium has emerged as a preferred base for flow batteries, because instead of two different substance a vanadium flow battery relies only on one: vanadium. That eliminates the cross-contamination issues that typically complicate flow battery design.

As for how one substance can stand in for two, that’s because vanadium can exist in two different states.

The problem is that until very recently, the domestic supply of vanadium has been highly problematic to say the least. However, the nation’s first and only vanadium mine is currently revving up operations in Nevada.

Meanwhile, Imergy has come up with a sustainability-minded solution of its own, which is to reclaim vanadium from existing sources in the mining and fossil energy sectors, including mining slag and fly ash.

The question here would be whether reclaimed vanadium can match virgin vanadium in terms of quality, and Imergy appears to have answered that question.

The new ESP30 series will be based on reclaimed vanadium. Here’s a rundown from Imergy’s press materials:

The ESP30 series has a power capability of up to 50 kilowatts (kW) and can store up to 200 kilowatt hours (kWh) of electricity. The power and capacity of the ESP30 make it well suited for a variety of demanding energy storage applications, including peak shaving, demand response, energy shifting, renewable energy firming, and microgrid or back-up power.

In addition, ESP30 is designed as a modular system that can be transported in standard 20-foot shipping containers. The modules can be linked together for increased storage capacity.

Imergy also cites advantages over lithium-ion technology including the flow battery’s hardiness over a wider range of temperatures and its replaceable components, which provide it with an “effectively unlimited” useful life.

Among the applications envisioned by Imergy are microgrids in remote locations, and to that end the system can be operated remotely.

ESP30 will be available for sale in the US and India starting in November, so go for it all you early adopters.

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Written By

Tina specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.


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