A simple question? Like so many energy questions, what is a battery, is changing. The racks upon racks of round and rectangular batteries in a big box store are a small part of the definition now. Those batteries rely on chemical reactions for power. Here’s one definition.
“Battery” power can be created in non-chemical ways. Energy storage is a term that opens up the evolving perspective on batteries, stashing energy in some form for later use.
The Upstate of South Carolina has a facility that opened my mind about energy storage. Near Greenville is the Duke Energy Bad Creek facility. It is a pumped hydro power facility.
In simplest terms, a lake higher up releases water through turbines to a lake below and makes power. This is done when there is high energy demand – think hot summer days.
The Bad Creek facility is near the Oconee Nuclear Station, so at night when power is not in high demand, the upper lake gets refilled, pumped in using nuclear energy. Then this battery is ready to make more power.
Compressed Air Energy Storage (CAES) is another kind of energy source. Air is pumped into underground formations and released to generate power when needed. There’s a plant in McIntosh, Alabama.
Old caves and mines can be used to store the compressed air sometimes. That is a good use of existing resources. “Utilization of the very large air storage capacity available in porous rock structures enables a CAES plant to offer a unique combination of attributes including grid-scale energy storage capacity, seasonal load shifting, load balancing, peaking reserve.”
The diagram here is from a Pacific Northwest concept.
Thermal energy storage (TES) saves thermal energy by heating or cooling a storage medium (water, molten salt, rock) so that, “the stored energy can be used at a later time for heating and cooling applications and power generation. TES systems are used particularly in buildings and industrial processes.” (Source)
These are just a couple of the ways to store energy. New ideas are being researched.
Why store energy?
Flexibility. Energy storage enables better use of power – holding power until it is needed most. For instance, a friend in Minnesota’s power business told me how the wind there blows at night, at a low point for energy needs. If that wind power could be stored until it is needed during the day the power benefits the region.
Expect more research into various kinds of energy storage and how they can be deployed, from huge systems to many small storage units in your home (maybe even your electric vehicle). Consumers will have decisions to make about energy storage and how to use it.