Imergy’s Vanadium Flow Batteries Go to Work in China

(3BL Media/Justmeans) - Here is a great example of the changing of the guard in the energy sector. Concerns about air pollution, cost, and theft have led telecom companies in China to swap out their diesel generators and replace them with vanadium flow batteries as a power source for their rapidly expanding cellular network.

The company providing the batteries is Imergy Power Systems. I spoke with Imergy President and COO Tim Hennessey. He said that by putting solar panels on the towers, they could power the towers for 8 cents a kWh, as opposed to 40-50 cents using diesel. But, using batteries provides flexibility. The power can also come from the grid. They also have the option to charge them up using diesel when prices, which tend to fluctuate wildly, are low. According to Hennessey, as many as a million towers could eventually be involved. Imergy is working with Juno Capital Group to implement this deal.

Flow batteries represent a branch of the battery development tree that was aimed at large scale applications, like utilities. The difference between flow batteries and other batteries is the architecture.

While most batteries are designed for portable use with an emphasis on compact size, flow batteries forego this in exchange for a number of performance advantages.

By configuring the batteries so that the electrolytes are stored in separate tanks rather than residing in the power cells, they get very fast charge and discharge times, extremely long life and they can be designed with energy and power specified independently.

This last item is a big deal. Most batteries give you a set power output for a given energy capacity, they are linked by the underlying chemistry.

So, generally speaking, if you need a burst of power, then you need to buy a large battery with a high energy capacity--and pay accordingly Not so with a flow battery, if you want high power/low energy or vice versa, just specify that and you pay for just what you need. For utility applications such as this one, energy is far more important than power.

Speaking of cost, the economics are good because of the extremely long life. Unlike most batteries, electrodes are not consumed by the reaction. The fact that vanadium is a very abundant element which also helps keep the cost down.

But this is not something you would ever expect to see in your laptop cell phone. A typical 5 kW Imergy battery is about the size of a small dumpster. But then again, one of those could power a 5 HP motor for five hours wiht pwer to spare.

The other thing that makes the economics of these batteries is their considerable life expectancy. Unlike many other batteries where the chemical reaction that produces power also consumes the electrodes, that is not the case with these. A single battery should last the life of a long-term project, while other batteries might need to be replaced several times. Efficiency, at 75%, is a little below the best out there, but from a cost standpoint, these are quite attractive.