Back to the Blog
How is Renewable Energy Stored?
June 05, 2019
As we continually rely on clean and renewable energy
sources, such as hydro, thermal, wind and solar, new challenges are presented
with the impact their intermittent flow has on the grid. Storage of energy to
reliably cover the times the sun isn’t shining and the wind isn’t blowing
requires a realistic solution.
The electricity grid requires supply and demand to be equal
and constant adjustments to the supply are needed to mirror anticipated and
unexpected changes in demand. These changes in demand consist of conditions
like our typical daily routines, storms, equipment overloads and increased
usage from sudden extreme temperature change.
Energy storage is an imperative piece of the delicate
balancing act required to maintain the grid. Now, more than ever, the quest to
create a more flexible and reliable grid is a challenge.
So How is Energy Stored?
- Batteries – Though batteries have been around for a quite some time, their technology has recently advanced due to the increasing use of electric vehicles. There are many types of batteries that have large-scale storage abilities and are excellent for storage because they can be located anywhere. Batteries increase the stability of the grid because they can be placed near consumers to provide power or near facilities, such as wind farms, for storage.
- Compressed Air Energy Storage – This method improves upon the efficient conventional gas turbines by compressing air during low demand times and storing it in underground caverns. When there is extra demand on the grid, air is pulled from the caverns and fired with natural gas in a combustion turbine to generate electricity.
- Flywheels – A flywheel is a cylinder-shaped device that contains a large rotor inside a vacuum. It spins at a very high speed, pulling electricity from the grid and storing it as rotational energy. It releases energy back to the grid by slowing the rotor and running on inertial energy.
- Pumped Hydroelectric Storage– One of the oldest forms of energy storage is the pumping of water into higher elevation reserves or behind hydroelectric dams during low usage. Water then flows into the turbines, during periods of high demand, adding more capacity to the grid when needed.
- Thermal Storage of the Sun’s Heat – Uses power from the sun by capturing the heat and storing the energy in water, molten salts or other liquids. This can later be used to generate electricity, which enables the use of solar energy even when the sun isn’t shining.
- Thermal Storage by Freezing Water – Another thermal storage technology includes freezing water at night when electricity usage is low and using the ice during the day to condense air conditioning system refrigerant. The electricity consumption is shifted from the daytime when the grid demand is highest to a time when there’s less demand and electricity costs are lower.
What are the Benefits of Energy Storage?
Stored energy’s largest benefit is that it’s discharged to
the grid rapidly as opposed to energy derived from fossil fuels, which takes
significantly more time. Quick responses create more stability for the grid
during times of unexpected increase in demand.
Storage is also crucial the farther away a home or business
is from the grid. There is a higher probability of disruption in electricity
flow for those in rural areas versus in metropolitan areas, which means storage
facilities are necessary to ensure power stability for outlying areas.
As use of renewable energy continues to expand, there are
several ways to take control of your own energy spend. Do-it-yourself
energy audits are a good start. Updating old appliances and
machinery, as well as installing smart thermostats to control unnecessary use
of temperature control when you’re not at your home or business can help.
Check out AEP Energy’s renewable energy supply price plan
for your home or business! This plan allows you to match 100% of your
electricity usage with Renewable Energy Certificates (RECs), which supports
renewable energy resources.
Learn more about AEP Energy’s renewable energy supply price
plan by visiting our website.