Zinc-Air Batteries: A Game Changer in Grid-Scale Energy Storage?

This article is a contribution from the good folks over at EnergyInformative.org.

Solar and wind energy will rapidly increase over the coming years all over the globe. Unfortunately our grid is not suited towards these two renewable energy sources.

The first reason for this is that, as with the weather forecast, both of them are highly unpredictable. Calculating wind and sun exposure into the future is incredibly hard and we seldom get accurate results. This simply won’t cut it for the consumers. We need a rather stable flow of energy and by using energy storage we can achieve this.

Then we have days where there is a surplus of energy generated by these technologies compared to the consumption. This is also the case with wind turbines during the night. Even though the energy generation is low, we tend to spend a lot less energy when we’re sleeping. This ultimately leads to a waste of useful energy – if we don’t take measures to store it.

Image credit: ReVolt Technology

There are many technologies we can use to store energy, some proven to be a lot more efficient than others. Pumped water storage is by far the best one yet, but unfortunately this method is only suitable on certain locations.

One would think that batteries would be a first pick when it comes to storing energy. The technology is well developed at the consumer level in everything from cell phones to electrical vehicles. The thing is that the game totally changes when the scale goes up. Battery technologies that are efficient on consumer scale will end up with enormous costs if we were to use them on the electrical grid.

Zinc-air could be a game changer. The concept of this technology itself has been around for many years (see this 2009 report from Treehugger). However, in the recent years there has been a lot of progress. In theory, zinc-air should now have the efficiency to compete with other large-scale energy storage methods such as Flywheel energy storage and compressed air energy storage (CAES). The same goes for cost-efficiency. These are the reasons why:

Energy Density

The chemical reaction that drives energy out of these battery types has two main components  (or reactants): Zinc and air. Since air is not stored in the battery itself, but taken from the outside, size is vastly decreased. A zinc-air battery should be able to store just as much energy as most other battery types with a size several times smaller.

Performance

The zinc-air technology has shown to have good performance in testing phase. Most important features include good charge/re-charge capabilities, as well as a long lifetime. These things are crucial in a grid-scale setting.

Good Market

Zinc-air is not only applicable for the grid-scale. In fact, the biggest market for zinc-air batteries is the electrical vehicle market. Think about how many vehicles are in use today, which most of eventually will be replaced by electricity-driven ones. The motivation for further developing zinc-air should be clear.

It looks like zinc-air could be a good challenger to flywheel energy storage and compressed air energy storage (CAES). It will be interesting to see if zinc-air is as good in reality as it is on paper. EOS Energy Storage has promised delivery of the first MW scale systems already in 2013.

Energy storage is only a small piece of a big puzzle that needs to be solved if we were to transition successfully to renewable energy sources and a greener world. Read more at EnergyInformative.org.

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