A New Sodium-Ion Battery Twist In The Tale Of ESS

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Despite the sharp U-turn in federal energy policy, the march of decarbonization continues. Exhibit A is a new, 8.5 gigawatt-hour partnership between two US energy storage innovators, featuring the Oregon startup ESS Tech and the Massachusetts sodium-ion battery specialist Alsym Energy…wait, ESS is still alive and kicking?

Yes, ESS Is Still Alive, Kicking, And…

ESS surfaced on the CleanTechnica radar five years ago, brimming with confidence over the future of its new long duration flow battery. The startup was developing the technology with the help of a $2.8 million award from the ARPA-E office of the US Department of Energy.

“The ESS flow battery technology is distinguished by its cost-effective electrolytes, based on earth-abundant iron, and its innovative battery hardware design that dramatically increases power density and enables a smaller and less costly battery,” ARPA-E enthused back in 2016, when it announced the award. ARPA-E also anticipated that the lower-costing, higher-performing battery would help shepherd more wind and solar energy into the grid, by offering many more hours of storage than conventional lithium-ion batteries.

With the funding in hand, ESS did not let the grass grow under its feet. “ESS showcased its all-iron flow battery at Intersolar North America in 2017 and reached another milestone in 2019 when the US Department of Defense — a big fan of clean tech — installed the company’s Energy Warehouse™ flow battery at Marine Corps Base Camp Pendleton in San Diego,” CleanTechnica reported in 2021.

…Manufacturing A Sodium-Ion Battery Now

ESS ran into some financial difficulties last year, but rumors of its demise were greatly exaggerated. Last week, Alsym Energy announced that it tapped ESS to manufacture its new sodium-ion battery.

For those of you new to the topic, the sodium-ion or “salt battery” formula is new to the commercial-scale energy storage scene. Compared to the more familiar lithium-ion technology, a sodium-ion battery has the potential to cut costs and improve performance, while reducing if not eliminating fire risks. On-shoring the materials supply chain is another plus (see more sodium-ion background here).

Of course, the devil is in the details. Getting sodium to behave in a rechargeable battery has been a tough row to hoe, as demonstrated by the flameout of the once promising sodium-ion battery maker Natron. However, other US energy storage innovators have been picking up the slack, and Alsym is one of them. The company announced the commercial launch of its new battery last October, and now comes the new partnership with ESS.

The Sodium-Ion Advantage

The hookup with ESS enables Alsym to leapfrog up the scale-up ladder. With the signing of a letter of intent, ESS has committed to manufacturing 8.5 gigawatt-hours of sodium-ion cells and modules.

As for whether or not the new battery can compete head to head against lithium-ion on cost, that’s a good question. Alsym anticipates that the up-front cost will be offset in a TCO (total cost of ownership) framework, particularly in regards to avoiding fire hazards.

“This next‑generation battery solution is designed to address use cases traditionally served by lithium‑ion systems – and those where lithium cannot go – but without the inherent thermal run-away risks associated with lithium chemistries,” Alsym explains.

“The Alsym sodium-ion technology virtually eliminates thermal runaway risk and lowers total cost of ownership,” the company adds. “In addition, the solution does not require complex HVAC systems, demonstrates high round trip efficiency, employs fast charge and discharge capabilities and offers a simpler, safer deployment profile.”

How Will ESS Pull Off The Switcheroo?

The next question is how ESS expects to wedge a sodium-ion battery into its portfolio after spending more than 10 years focusing on flow batteries. That is also a good question. By way of an answer, ESS affirmed that it intends to keep its 8-24 hour flow battery in play for long duration applications, while the Alsym sodium-ion battery fills in for shorter spans of time. The aim is to provide one seamless package to clients that need both long- and short-duration storage systems.

“Sodium-ion and iron flow are complementary technologies,” explained Drew Buckley, the CEO of ESS. “Alsym’s sodium-ion Na-Series is an ideal solution for ESS’s short- and medium-duration applications where high power, fast cycling, and rapid response are paramount.”

“ESS’s existing Energy Base® iron flow platform is engineered for the 8–24 hour long-duration segment, where deep daily cycling, 25-year asset life, and zero capacity degradation deliver the lowest levelized cost of storage,” Buckley emphasized. “Together, the two chemistries form a unified, non-lithium platform that enables ESS to meet customers’ full storage needs from a single trusted provider.”

ESS Chief Commercial Officer Randall Selesky also had plenty to say on the subject. “By combining Alsym’s high performance, non-flammable sodium‑ion technology with ESS’ systems expertise and Energy Base® long‑duration solutions, we are giving customers a clear pathway beyond lithium‑ion — without compromising performance or economics.”

“Unlike lithium‑ion batteries and many other sodium-ion batteries, Alsym’s Na-Series batteries are non‑combustible and thermally stable, reducing system complexity, improving safety, and lowering total cost of ownership by reducing the need for extensive fire suppression and HVAC infrastructure,” Selesky added for good measure.

Next Steps For Energy Storage

ESS is also on the prowl for new opportunities in the global energy storage market. Last year, the German iron-salt battery startup VoltStorage declared bankruptcy and ESS has picked up the pieces, acquiring the firm’s intellectual property among other assets.

The leading global communications and research firm Mercom Capital took note of the acquisition in February. “As part of the transaction, VoltStorage’s key executive and engineering teams will join ESS, strengthening the company’s commercial and technical capabilities,” Mercom observed.

“The combined technology is expected to offer a wider range of applications, from grid-scale storage to industrial microgrids, and to deploy international development expertise at ESS’s American manufacturing facility,” Mercom added.

Buckley also emphasized the global focus. “This acquisition accelerates our mission to provide clean, reliable, and affordable energy storage solutions worldwide,” he said in a press statement.

Global is the word. US President Donald Trump has pulled out all the stops in an effort to prevent more wind and solar energy from prying their way into the domestic power generation picture, but innovators here in the US can just pack up their wares and go elsewhere around the world.

For that matter, wind, solar, and energy storage — particularly solar and storage — are continuing to add new generating capacity in the US at a rate that absolutely crushes the next-closest competitor, natural gas. If you have any thoughts about that, drop a note in the comment thread.

Photo: Alsym Energy launched its new sodium-ion battery into the market last year, and now it is on track for volume production under an 8.5 gigawatt-hour agreement with the US energy storage startup ESS (courtesy of Alsym).