A few interesting things here : • The article is from August...

A few interesting things here :
• The article is from August 2013
• NGK had a contract for up to 490MW earlier with Terna SpA of Italy - there had been a battery fire in Sep for Sodium-sulfur batteries
• Sumitomo mentioned once again - we still don't know who TNG's MOU is with
• Japanese Nuke plants are having trouble getting permission to re-start after Fukushima - http://bit.ly/1SiqYLg
Court issues surprise injunction to halt Takahama nuclear reactors

A few issues with Vanadium Redox batteries I stumbled across include :
- They depend on the concentration of the vanadium species and are limited to the vanadium concentration.
- If the concentration is too high, precipitation occurs.
- Temperatures of above 40 deg or below 10 deg cause precipitation.
- The highly oxidising nature of V5+ causes degradation of the ion-exchange membranes and the positive electrode material meaning.
- This limits the positive electrode material to either carbon of graphite felt.
- Nafion membranes are stable in V5+ but are quite expensive.

Over 8 years Sumitomo would certainly be capable of solving these issues with Vanadium flow batteries...
Sumitomo started research in 1985 and suspended work because the batteries kept charge more briefly than expected. It resumed in 2008 and this year set up a division to promote the technology, said Mitsuyo Tsuruta, a Sumitomo spokeswoman. It has been conducting pilot projects and wants to commercialize the battery as early as next year.
• Researching since 2008 - 8 years, but research efforts go back a further 23 years to 1985
• Largest installed system pretty much anywhere - 60MWh
• One megawatt is enough to power about 333 homes in Japan.

The 1MW per 333 homes is kind of important, IMO - Imergy were aiming f0r $300kWh storage - or $300,000 per MWh. Rounding up to say $333,000 - $1,000 per home in Japan...

If Sumitomo can get the pricing point of battery storage so that a one off $1,000 will store and then supply a home's electricity needs for the evening, that will change the electricity industry significantly. Remembering that Elon Musk's stated aim is below the $100 kWh level...