8.5 Giga-watt-h battery (!) to be built

[Dennis P Brown]

A rather surprising accouchement by the same company that is currently building a 150 MWH storage system in Cambridge, Minnesota. This is, to say the least, a rather extreme jump in storage capability at 8.5 Giga-watt-hours of storage. If they succeed this will be a rather extreme jump in Iron-air battery tech and really put that type of storage system on the map.

See: https://www.livescience.com/technology/ ... rgy-laptop

[Rich Feldman]

Thanks for passing along good news. I've long said that grid scale battery technology will move away from lithium ( except for putting power into grid from plugged-in EV's ).
The cited article fails to mention the mature technology of pumped hydroelectric energy storage. In places with favorable geography, its cost and energy loss fraction can't be beaten by practical batteries today.

[Bob Reite]

I really don't understand why they are not using nickel-iron cells for grid storage. Yes the energy density is not all that great, but you aren't trying to fit it in a vehicle. Land can't that be that expensive. There are so many advantages to this technology. Deep cycling does not hurt them. They last for 30 to 50 years with proper care. The somewhat fast self discharge rate would not be a problem for solar farms, as they would get recharged on a daily basis. Only possible problem is that they don't do well at high rates, but several parallel connected banks should mitigate this problem.

[Dennis P Brown]

Partly because it is hard to get major players to trust new tech. Then one needs a factory big enough to make the necessary units (getting that money can be hard w/o existing customers ... chicken and egg issue there ). Further, proven that they can do a large scale project is a big barrier. This company got the necessary funds for a fairly large scale system and now, someone else appears to trust that they can go even bigger time. So, looks like iron-air batteries might start gaining momentum now. That is, IF they build all the units and said units work as promised.

[Bob Reite]

Nickel Iron batteries are OLD tech! Edison patented and commercialized them in 1901!

[Dennis P Brown]

The issue is, as you mention, that battery system uses Nickle. That is an expensive and extremely dirty to manufacture component; much of the world's supply comes from Russia, if memory serves. Iron-air uses only iron and a special electrolytic that, apparently, is easy to process and dispose. While this battery is large and heavy it cycles a huge number of time and is easy to recycle w/o environmental issues. I'm certainly not concerned by this fields complex trade off's but from cursory reading, this battery has a large number of advantages. There are reasons that one system is selected over another and modern batteries certainly have advanced by impressive amounts.

[Bob Reite]

Yes, good to be rid of the nickel. I'm sort of amazed that they were able to make iron-air work as a rechargeable cell as compared to a primary cell that can be discharged only once, such as Zinc-air cells commonly used in hearing aids.

[Frank Sanns]

The losses with batteries can be huge. Lithium based batteries are up around 90% for each charge cycle. Putting a MWH into a battery loses 100 KWH every time it is cycled. Energy is also lost continuously by self discharge.


The iron-air battery is only 50% efficient so every time a MWH is put in, only 500 KWH can recovered on each cycle. Ouch!

[Dennis P Brown]

The reason this type of system is so cost effective is the energy is basically "free"; that is, it is excessive energy that isn't needed during time of production via the carbon free systems. Either from wind and/or solar in most cases (nuclear would certainly not need this but that is another story.)

So this extra energy is stored and then used after the wind dies or the sun sets/clouds (in California this has become a huge bonus to their extensive solar supported grid*) enabling day solar to be used through the early evening during high usage times. This supplies the majority of their energy needs. So recovered vs. lost energy during battery cycling isn't such a big deal. Even more so if the battery is low cost, simple, and easy to maintain/upgrade.

However, battery cycle life is absolutely critical and there iron-oxygen batteries are extremely useful with their extremely long cycling lifetimes. A big bonus is they are so easy to recycle when at the end of their lives. Of course, availability of the primary resources is a non-issue.

Are there down sides - just as you posted (and that is a significant one for carbon based generation systems) - so, yes; and no one except some deep pocket guys making a killing down in Texas want to use these with conventual power generation. But for wind/solar electric grid support this is really a big breakthrough enabling the critical evening power availability that previously, was the "big bug-a-bear" that everyone said would prevent clean power from being exploited. That is being put to rest big time if this turns out to be most of what its backers claim. Apparently, people are putting this to a real test which is good. So, both the real world conditions and bean counters will all have the final say in this new battery system.

* I am NOT a fan of the lithium storage system they use (cobalt is an extremely dirty to produce; even if that is eliminated, Li is a problem in many ways); These Li-Co batteries are difficult to recycle and the entire worlds supply of Li is very, very limited. The exact opposite of Iron-oxygen batteries.