Flowing electrolyte prototype used to regulate the electrical grid. (via ZBB Technologies)
The rise of green energy such as solar cells and wind turbines have given rise to new ideologies for powering our electrical grid. Microgrids, or localized energy sources, can possibly be integrated into the power grid to help provide backup energy during times of need or in times when electricity prices from the grid peak. In order for this to work, there has to be efficient methods for storing energy from green sources. A few companies experimenting with these methods are hoping that flow batteries could be the solution for future storage of energy.
Flow batteries work from three fundamental parts. There are two electrolytes, which are separated and stored in two different tanks, and there is a cell stack. When the two electrolytes are pumped into the cell stacks, they create chemical reactions by flowing past a porous membrane. As a result, ions or electrons flow back and forth, depending on whether the battery is charging or discharging. Creating more energy storage only consists of making larger tanks, which the batteries themselves can be as large as shipping containers. One down side is that the batteries at times can be difficult to maintain. On the other hand, they are considered safer than conventional batteries, which are prone to thermal runaway resulting in fires.
Designs and new ideas for more efficient flow batteries are currently being worked on by companies such as Primus Power, Deeya Energy, and EnerVault. EnerVault is experimenting with batteries that use an iron chromium chemistry which are one-sixth the cost of the traditionally used materials. Bret Adams, EnerVault's director of business and development, stated, “We started with readily available commodities – iron and chromium. Even if we were massively successful, we'd be using a very small potential piece of that supply.” EnerVault's technology is still being developed and the company is planning on testing out a number of different systems throughout the course of this year.
Flow batteries can open up the possibility of providing local areas with back up power in the case of electrical grid failures. For example, in 2011 a massive blackout hit San Diego. The Marine Corps Air Station nearby had a 230-kilowatt solar array on the location, however, it was not meant to be used as backup power and generators had to be used to temporarily power the base until the power came back on.
In another example, Gills Onions, an onion farm in southern California uses agricultural waste to produce energy. When the electrical grid prices rise, the farm can use an on site battery to provide 600 kilowatts of energy for around six hours. These are all examples of how microgrids can help provide us with power in the future. Whether it is to save money or an emergency situation, neighborhoods, businesses, cities, and farms can all benefit from microgrids in the future.
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