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03 August 2013

Zinc-air electrical storage ready for grid testing

One of the technologies I have been following closer in recent times is metal air electricity storage. The principle seems simple enough: an aqueous solution (the electrolyte) containing metal particles (anode) that oxidate in contact with ambient air (cathode), thus releasing free electrons. Zinc-air batteries in particular have been in the market for long; cheap to produce and with high energy density, they are used in a myriad of applications. The only downside: once the metal in the solution has fully oxidated, the battery can at best end up in recycling.

Recently though there is an American company that has developed a rechargeable zinc-air battery design that promises to bring the electricity storage market up side down.

There are three characteristics to this battery technology that make it sound rather promising:
  1. Cost - at 160 dollar per kilowatt-hour capacity ($/kWh) it is close to a fourth the cost of lead acid batteries, the most common technology today.

  2. Longevity - the company claims a lifetime of 30 years, although this is something only real life operation can assure. Still, at the stated cost even a lifetime of a decade can grant an advantage above all market ready solutions today.

  3. Liquid electrolyte - theoretically capable of fitting containers of different sizes and shapes. Combined with the previous characteristics it creates some interesting opportunities for mobile applications.
No wonder then that some grid heavy weights are partnering with the development company. Even if it can deliver on only half of its promises this technology is already a major step ahead; if it fully delivers on claimed costs and longevity, then a revolution of the electrical grid becomes a possibility.

Here's a long presentation mandatory to understand the full potential of the technology:

A pilot test project with a 1 MWh grid size block is set to start with the Consolidated Edison company in New York in a few months. Other pilot tests of the same size should start during 2014. Some recent updates by the media:
The zinc-air battery startup reveals Enel, GDF SUEZ, National Grid, NRG, PNM, BASF as new partners.
Jeff St. John, 17-07-2013

Eos Energy Storage has been saying for months that it’s working with a global list of utility partners interested in bringing its zinc-air grid battery technology to commercial scale. Now the New York-based startup revealed those partners, including several of Europe’s biggest utilities, as well as one of North America’s most innovative ones.

On Tuesday, Eos announced that it’s added national Italian utility Enel, French power and water giant GDF Suez, U.K.-based powerhouse National Grid, U.S. municipal utility Public Service Company of New Mexico (PNM), and Princeton, N.J.-based multifaceted energy company NRG Energy, to its “Genesis Program” list of utility partners.

Under the program, which already counts New York utility Consolidated Edison as its first real-world demo partner, Eos will be working on “business case evaluation, product development and optimization, and pilot demonstration of Eos’ innovative battery technology,” according to Tuesday’s statement. Eos also announced it’s in a joint development agreement with BASF New Business GmbH, a unit of German chemical (and battery technology) giant BASF, to “enhance Eos’ battery technology and to support its Genesis program.”
Eos Energy Storage Getting Closer With Zinc Air Batteries
Stuart Burns, 22-07-2013

Although electricity storage is the holy grail for generators and transmissions -irms, the ste-ps to get there don’t come without some hiccups.

Compressed air systems cannot be reversed to power production from power storage in the milliseconds the industry would like, and below-ground storage sites are often not in locations close to major conurbations, while above-ground storage is not a major attraction in residential areas for obvious reasons. Sodium-Sulfur, while a vast improvement on Lead Acid and Lithium Ion, is still an expensive storage technology, which accounts for its slow uptake so far.

An old technology highly refined is purporting to have the answer, according to the NY Times. Eos, a US firm, has refined the Zinc Air battery to the point where in tests, batteries are exceeding 10,000 cycles and life expectancy of 30 years is a realistic expectation.
And here's a recent interview to the company president by Platts Energy Week:

I'll continue following this technology with expectation.

P.S.: There's a clear slow down in energy related news due to the aestival vacation. The press review will be back once things warm up again.