Short news on NAS batteries

NGK’s NAS batteries are restarting

Existing NAS batteries systems are rebuilt by NGK Insulators Ltd. to reduce potential fire risk. Slowly, but surely, the fire incident of September 21, 2011, becomes a classified event.

xcel-energy-logoFor instance, Xcel Energy now announces it is restarting its battery plant that was commissioned in 2008 and stopped on NGK recommendation after the fire incident in Japan.

GE continues to massively hire storage experts

geThere are still ten open job positions related to Durathon on GE web site. There is even one in Japan for a Field Services Engineer, in the middle of NGK playground.

More than ever, a leading technology for grid applications

sodiumIn a recent article “Dynamic Modelling of Advanced Battery Energy Storage System for Grid-Tied AC Microgrid Applications“, researchers concludes:

“Sodium sulfur-type BESS devices are best suited to the requirements set by modern microgrid applications. These batteries can act in contingencies where rapid action is required to maintain the adequate levels of the grid frequency, but also in the case of high penetration of renewable generation, such as wind or solar photovoltaic, since the NaS battery can operate as the perfect complement in valley hours. In this case, the excess energy can be stored for delivery in peak hours. They are environmentally safe and have low maintenance while operate at high temperatures; it does not represent a major drawback. The biggest drawbacks are the cost and the limited information about these type of batteries which difficult the development of experimental prototypes and computer models. It is expected however that the appearance of other vendors reduces costs and facilitate the modelling.”

It is one of the numerous independent studies that recognise the advantages of NAS compared with other technologies for grid storage solutions.

Gauthier Dupont
Dupont Energy Consulting GmbH

GE and NGK spare no expense on molten salt batteries

Hustle and bustle in Schenectady, NY, USA

“GE Energy Storage is now open for business”, one can read in a recent General Electric video. The production commenced in September 2011. The Durathon™ battery factory officially opened on July 10, 2012, in Schenectady, NY. $100m were initially invested. Additional $70m are already committed to double the plant capacity.

It took three years at GE’s Global Research Center in Niskayuna, NY, to improve and perfect the technology bought in 2007 from Beta Research & Development, a UK company. And one years to build the plant.

Hundreds of new jobs were created. There are today 45 job offers on GE’s website. At full capacity, the factory will employ 450 workers and drive thousands of additional supply chain jobs throughout the region.

The first order was signed by Megatron Federal, a South African company, which will install 6,000 batteries in Nigeria to keep its telecom installations running during all too common power disruptions, decreasing its dependence on diesel backup generators, lowering fuel consumption and CO2 emissions.

Orders raise to $63m from about ten or so telecom customers.

Slow and steady in Nagoya, Japan

In his Fiscal Year 2012 2nd Quarter Results presentation, NGK Insulators Ltd. explains his strategy to reignite NAS batteries market:

  • Future trend:
    • Increasing overseas demand
  • Objectives:
    • To restore market confidence by implementing safety measures
    • To Expand sales of NAS batteries overseas and in renewable energy field
  • First steps:
    • Production priority put on safety measures
    • Resume production from November 2012
    • Overseas orders deferred to next year.

After the extraordinary FY11 (fiscal year from April 2010 to March 2011) losses of ¥4.8bn (€46m) related to NAS battery safety measures, sales of NAS batteries recovered at a slow pace in FY12 at ¥0.9bn (€9m) – see the figure opposite from NGK Insulators Ltd. But far beyond FY10 sales (¥19.7bn – €190m).

The deferment of order due to the priority put on safety measures is reflected in FY13 sales forecast that is as low as ¥0.2bn (€2m).

In NGK’s Summary of Consolidated Financial Results for the Six Months ended September 30, 2012, published on 31.10.2012, ¥38bn (€367m) are provisioned for NAS battery safety measures, down from ¥57bn (€552m) initially end of December 2011.

In nine months, 34% of the initial provision for NAS safety were invested. Taking into account NGK strategy explained above, one can expect that the remaining efforts would speed up, and that one year from now would be sufficient to completely solve safety issues. This assumption is in line with NGK announcement to defer overseas orders to next year.

The Hare and the Tortoise – Our Prediction

While GE is new in the race and try to force the pace, NGK, as usual, adopts an extremely cautious approach. Based on the moral of the tale, “slow and steady wins the race”, one could conclude that NGK is in best position.

But it would be too hastily, because GE and NGK are not (yet) playing in the same league:

  • NGK’ NAS batteries minimum size is one MW. The module are rated 50 kW, but they are not sold individually.
  • GE’s Durathon battery module delivers a few kW. Multiple Durathon modules can be connected in parallel if more capacity is needed. But they cannot be connected in series for higher voltage. MW range capacity then requires further developments.

They will then both win the race. Each on his own playground. NGK in large-scale grid applications, including integration with wind farms and large PV plants; and GE in medium-scale energy applications, like what they are doing in the telecom sector. But one day, both companies will meet in the same league. Then…

Gauthier Dupont
Dupont Energy Consulting GmbH

NGK’s NAS batteries long recovery


  • September 21, 2011 : Fire incident at the Tsukuba Plant, Joso City, Ibaraki Prefecture, Japan
  • September 22, 2011 : announcement of the event on NGK’s website
  • October 5, 2011 : fire authorities confirmed that the fire had been extinguished
  • October 25, 2011 : NGK requests all NAS batteries facilities to be stopped or to restrict their usage (after agreement with NGK)
  • October 28, 2011 : All shipments are officially postponed & business forecast is revised
  • November 24, 2011 : NGK publishes a Q&A on its website
  • June 7, 2012 : NGK explains the causes of the fire incident and countermeasures
  • From June 2012 : upgrade of existing batteries facilities
  • October 2012 (?) : batteries production resumed

Small cause, big effects

After months of silence, NGK finally communicates on June 7th, 2012, about the NAS battery fire incident. The cause: a single faulty cell. One of 15,360 cells composing a 2 MW block. The solution: safety enhancement. No need for design change. Big incident, easy solution.


Since June 2012, existing NAS batteries facilities are, one after the other, upgraded to safety enhancement, by implementing following measures to prevent the spread of fire in modular batteries :

  • Fuses between battery cells
  • Insulation boards between blocks in battery modules
  • Anti-fire boards above and below battery modules.

The two first measures requires about 6000 battery modules from 174 locations in Japan, France, Germany, UAE, UK and USA to be collected in NGK facilities in Japan and then shipped back.

Along with additional safety measures (improved fire monitoring system, installation of fire extinguishers and fire-prevention equipment), as well as facilities organisation improvement (setup of a fire-fighting structure on site and of a fire evacuation route, with guidance system).

Production of new batteries 

New batteries would be produced at the earliest in October 2012. Business development perspectives are nevertheless maintained, mainly because NGK niche market is waiting for their batteries. unless GE’s Durathon shows up…

Gauthier Dupont
Dupont Energy Consulting GmbH

Who are the direct competitors of NGK for NAS batteries ?

Here they are


Nagoya, this is the battery community, do you copy ?

Today, May 19th, 2012, exactly five months have gone since the last communication of NGK Insulators Ltd. about the NAS battery fire incident that occurred on September 21, 2011. We all get impatient to get more information and to know what they plan now.

I would like to address an open letter to NGK:

“Dear Mister President,
(or anybody else working for NGK and ready to share information),

Please, say something, please…

Best regards,

A worried member of the battery community”

Robinson Crusoe is never long alone on Technology Island

NGK is the only company which manufactures high-temperature molten salt batteries (also called molten metal). But some others companies are massively investing to fill the gap. Their “out-of-the-box” products would appear on the market within a few years, but I think that some are ready for pilot projects.

It takes time to restore customer confidence. When nobody will anymore talk about the fire incident, allowing NGK to completely recover, they will probably face stronger competition.

Basically, high-temperature molten salt batteries are characterized by:

  • A liquid anode (sodium)
  • A liquid cathode (Na2Sx for NAS batteries and a molten salt chloride for others, the metal being generally nickel, hence the name sodium-nickel-chloride batteries)
  • A sodium ion-conducting beta-alumina ceramic acting as solid electrolyte in NAS batteries or, in sodium-nickel-chloride batteries, as a membrane between liquid electrolyte (molten sodium aluminumchloride NaAlCl4) and the liquid electrodes
  • A high operating temperature (around 300-350°C).

NGK is the only company which manufactures and sells NAS batteries. Others invest in Sodium-Nickel-Chloride batteries (often called Zebra batteries), because the technology is slightly more promising:

  • Higher cell voltage (2.59 V instead of 2.076 V)
  • Wider operating temperature (270 to 350°C instead of 310 to 350°C)
  • Less component corrosion at the positive electrode
  • Slightly safer (lower exothermic heats and lower vapour pressure)
  • Tolerant to overcharge and short-circuit
  • Recovery of the nickel during recycling.

Let me introduce the key players

Actually, the most advanced NGK’s competitor is a swiss-italian consortium developing FIAMM Sonick’s Zebra batteries. But GE would also play a major role within a few years. They are investing hundreds of millions of dollars to develop similar technology, they call Durathon. GE maintains a continued relationship with FIAMM Sonick and bought BETA R&D in UK, to acquire the technical expertise, in particular the ceramic issues.

An eye can also be kept on the company Ceramatec, because they control the key issue of molten salt batteries: the ceramic and the ceramic to metal bounding technology. They have strategic partners, as mentioned on their website, but their name is kept secret. GE again?

Here below, you’ll find website links and documents that briefly present these companies and their strategy. If you have more information, I would be pleased to add them to the list.

GE Enters the Grid-based Energy Storage Business | Alternative Energy Stocks
GE Energy Storage Technologies – Durathon
GE and FIAMM Target Molten Salt Batteries. But Can They Compete with NGK?

FIAMM, Italy & FZSonick, Switzerland
FZ SoNick – Sodium Nickel Batteries
Balderrie Energie GmbH – ZEBRA batteries
Sodium Nickel Chloride “Zebra” Battery (Book)


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