Energy Storage Can Equal Energy Savings

SOURCE: ENERGY STORAGE ASSOCIATION; DESIGN: KEVIN KEPPLE

Energy storage devices absorb and store power, saving it for when it’s needed most.

In the private sector, batteries and other small-scale energy storage technology—in devices such as computers and smartphones—power our lives. But now it’s possible to store much more energy for personal use thanks to battery innovations like Tesla’s Powerwall, which stores solar energy for use when the sun isn’t shining.

Devices that can store large quantities of energy economically and over long periods can help utilities, including electric cooperatives, improve grid operations, integrate renewable energy and boost reliability, according to the National Rural Electric Cooperative Association.

For storing energy, four methods are widely used. 
 
Electrochemical
For this battery storage method with grid-scale applications, the most common versions use lithium-ion and lead cells. An electrochemical battery includes battery racks, cells, a temperature control, fire suppression and cooling vents.
 
Mechanical
The most common example utilizes a flywheel and compressed air to store energy kinetically. It features a vacuum enclosure, cylindrical rotor, motor, and upper and lower magnetic bearings.
 
Thermal
With a thermal energy storage unit, energy is stored as heat or cold, and controllable water heaters are the most common example. These devices are grid-enabled and contain a control panel that allows a utility to turn the heater off and on, regulate and shift load, and store energy at a low cost.
 
Gravitational
A gravitational storage device uses moved mass such as through pumped hydropower. A pumped storage facility might have a unit that contains an upper reservoir, generating and pumping areas, a turbine, and a lower reservoir.

As large-scale energy storage technology continues to improve, so will the reliability of intermittent renewable energy sources such as solar and wind, according to the Environmental and Energy Study Institute. The EESI also states that large-scale energy storage can react quickly to fluctuations in electricity demand, making the grid more responsive and reducing the need to build additional power plants.